Build Guide

2026-10-21T10:26:46Z

Mrothfuss: Added TPM information to the board overview. Put in a link to the Qubes OS page and moved the cpubug info there.

Qubes OS

2026-10-21T10:24:51Z

Mrothfuss:

Qubes OS is a reasonably secure operating system.<ref>https://www.qubes-os.org/</ref>

There is some overlap with user-base when you have a security focused operating system and a opensource bios. This page aims to detail some specific issues one might face when using Qubes on the 15h platform.

There is currently a cpupower bug in Xen and since qubes doesn't auto-pin cores the CPU won't throttle and idle properly so single lower wattage CPU's are recommended.

== Speculative execution mitigations ==
There are two Speculative execution vulnerabilities of intrest that is Inception and Retbleed the mitigations implemented in xen to patch these two vulnerabilities makes it impossible to run Qubes with a PCIe device attached to a qube<ref>https://github.com/QubesOS/qubes-issues/issues/9150</ref>

== Inception ==
Inception aka CVE-2023-20569 is a Speculative Return Stack Overflow vulnerability<ref>https://xenbits.xen.org/xsa/advisory-434.html</ref>
Following xens XSA-434 advisory qubes published QSB 093<ref>https://raw.githubusercontent.com/QubesOS/qubes-secpack/refs/heads/main/QSBs/qsb-093-2023.txt</ref> detailing the package versions containing the patches.
==== read more ====
https://xenbits.xen.org/xsa/advisory-434.html

https://www.amd.com/en/resources/product-security/bulletin/amd-sb-7005.html

https://comsec.ethz.ch/research/microarch/inception/

https://comsec.ethz.ch/wp-content/files/inception_sec23.pdf

https://github.com/comsec-group/inception

https://raw.githubusercontent.com/QubesOS/qubes-secpack/refs/heads/main/QSBs/qsb-093-2023.txt

== Retbleed ==
Retbleed aka CVE-2022-23816 is a Branch Type Confusion vulnerability<ref>https://xenbits.xen.org/xsa/advisory-407.html</ref>
Following xens XSA-407 advisory qubes published QSB 083<ref>https://raw.githubusercontent.com/QubesOS/qubes-secpack/refs/heads/master/QSBs/qsb-083-2022.txt</ref> detailing the package versions containing the patches.
==== read more ====
https://xenbits.xen.org/xsa/advisory-407.html

https://www.amd.com/en/resources/product-security/bulletin/amd-sb-1037.html

https://comsec.ethz.ch/research/microarch/retbleed/

https://comsec.ethz.ch/wp-content/files/retbleed_sec22.pdf

https://github.com/comsec-group/retbleed

https://raw.githubusercontent.com/QubesOS/qubes-secpack/refs/heads/master/QSBs/qsb-083-2022.txt

== Workarounds ==

'''This information is related to the Deprecated Raptor Engineering coreboot port'''

Fortunately there is workarounds that make the system usable without losing to much security and a limited performance impact. By setting the kernel paramter spec-ctrl<ref>https://xenbits.xen.org/docs/unstable/misc/xen-command-line.html#spec-ctrl-x86</ref> to spec-ctrl=ibpb-entry=no-pv as detailed under qubes issue 9150 will disable the mitigations for all pv qubes then all you would have to do is change the settings for any pcie dependent qube (ie sys-net and sys-usb) to be pv instead of hvm

=== instructions ===
in dom0 run the following commands

<code>
sudo echo 'GRUB_CMDLINE_XEN_DEFAULT="$GRUB_CMDLINE_XEN_DEFAULT spec-ctrl=ibpb-entry=no-pv" >> /etc/default/grub'

sudo grub2-mkconfig -o /boot/grub2/grub.cfg

qvm-prefs sys-net virt_mode pv

qvm-prefs sys-usb virt_mode pv

qvm-prefs sys-net memory 4000

qvm-prefs sys-usb memory 4000

reboot
</code>

=== security impact ===
if an attacker gets code execution in sys-net or sys-usb it is theoretically possible to leak secrets from other vms so make sure you keep all pv qubes very secure!

=== performance impact ===
According to news media reporting mitigations hurt cpu performance by 14~39%<ref>https://www.phoronix.com/review/retbleed-benchmark</ref>.

Measurements conducted by 15h.org member Arha utilizing qubes 4.2.3 in combination with the Heads bios and 2x AMD Opteron 6282 SE's running on the Asus KGPE-D16 produced a performance impact of ~27% noting qubes os was still very usable.

Build Guide

2026-10-21T10:14:06Z

Mrothfuss: Added more info to am3+ and rearranged. Replaced speculated gaming information with AM3+ experience. I don't think it is appropriate to tell people how they *should* use their device, people are here for various reasons beyond privacy/security.

[[File:Komos_sabertooth.png|thumb|[[Komos]] - a build using the [[AM3+]] [[Sabertooth 990FX R2.0]]]]
Since you're reading the 15h.org build guide, we'll assume you're interested in building a fully-FOSS-firmware-compatible AMD system to run [[coreboot-15h]]. This guide assumes you're looking to build a new desktop, server, or workstation system from separately-purchased components.

If you are ''not'' building from separate components (such as for the various prebuilt [[Supermicro]] servers which included compatible motherboards), head over to the [[Motherboards]] page and look for your board's model. For laptops, see the [[Laptops]] page.

== Choosing a Platform ==
coreboot-15h is available for many motherboards, across several different AMD sockets - which one you should choose depends on the balance of performance, cost, power consumption, and physical size you want for your system.

For an easy to build open source desktop, the [[Build Guide#Building with AM3+|AM3+]] platform is recommended. Compatible cases and [[Coolers|CPU coolers]] are easy to find. [[Build Guide#Building with AM3+|AM3+]] processors have the highest single core performance, making them the best choice for responsive activities such as web browsing or gaming.

Users that require lots of RAM (1024 GB max) or many cores (64 max) should look at the [[Build Guide#Building with C32|C32]] and [[Build Guide#Building with G34|G34]] platforms. The [[Build Guide#Building with C32|C32]] is the smaller of the two and is easier to build: motherboards can fit common cases and compatible [[Coolers|CPU coolers]] are easy to find. A more powerful system can be built with [[Build Guide#Building with G34|G34]], but compatible cases and coolers can be hard to find.

Small (mITX to uATX), low power (25 to 40 W) open source machines can be built using the [[Build Guide#Building with AM1|AM1]], [[Build Guide#Building with AM3+|AM3+]], and [[Build Guide#Building with C32|C32]] platforms.

Many of the supported platforms can use ECC memory and have a working IOMMU. ECC memory support is important for machines running nonstop over long periods of time. The IOMMU enables PCIe device isolation or passthrough to a virtual machine.

'''Qubes:'''

While most of the systems besides the AM1 fit all the requirements only the KGPE-D16 supports a TPM 2.0 module.

('''TODO:''' Check Supermicro systems for TPM support and see if it works without the VGA/BMC blob)

There is currently a cpupower bug in Xen and since qubes doesn't auto-pin cores the CPU won't throttle and idle properly so single lower wattage CPU's are recommended.

{|class="wikitable" style="text-align:center;"
|+
! rowspan="2" |Socket Type
! colspan="4" |Motherboard
! colspan="4" |Per Socket
! rowspan="2" |ECC Support
! rowspan="2" |IOMMU Support
|-
!Size
!CPU Sockets
!Model
!Type
!CPU Cores
!Max Frequency (GHz)
!CPU TDP (W)
!Max RAM
|-
|[[Build Guide#Building with AM1|Socket AM1]]
|mITX
|1
|[[ASRock AM1H-ITX]]
|Desktop
|2 to 4
|2.20
|25
|16 GB
|Yes
|No
|-
| rowspan="3" |[[Build Guide#Building with AM3+|Socket AM3+]]
|uATX
| rowspan="3" |1
|[[Supermicro H8SML]]
|Server
| rowspan="3" |4 to 8
|3.80
|25 to 65
| rowspan="3" |64 GB
| rowspan="3" |Yes
| rowspan="3" |Yes
|-
| rowspan="2" |ATX
|[[ASUS Crosshair V Formula-Z]]
| rowspan="2" |Desktop
| rowspan="2" |5.00
| rowspan="2" |25 to 220
|-
|[[ASUS Sabertooth 990FX R2.0]]
|-
| rowspan="2" |[[Build Guide#Building with C32|Socket C32]]
|uATX
|1
|[[Supermicro H8SCM]]
| rowspan="2" |Server
| rowspan="2" |4 to 8
| rowspan="2" |3.80
| rowspan="2" |35 to 95
| rowspan="2" |256 GB
| rowspan="2" |Yes
| rowspan="2" |Yes
|-
|SSI CEB
|2
|[[ASUS KCMA-D8]]
|-
| rowspan="3" |[[Build Guide#Building with G34|Socket G34]]
|ATX
|1
|[[Supermicro H8SGL]]
| rowspan="3" |Server
| rowspan="3" |4 to 16
| rowspan="3" |3.80
| rowspan="3" |85 to 140
| rowspan="3" |256 GB
| rowspan="3" |Yes
| rowspan="3" |Yes
|-
|SSI EEB
|2
|[[ASUS KGPE-D16]]
|-
|SWTX
|4
|[[Supermicro H8QG6]]
|}

All of these platforms besides the AM1 support ECC memory, IOMMU, SR-IOV, SLAT, PCI-e ACS and are based on [[Orochi]] - AMD's high-power, high-performance platform for [[Family 15h]] systems.

If you're looking to build a lower-power quad-core system (such as for an efficient router or media player machine), you may be interested in a [[Trinity|Trinity/Richland]] or [[Kabini]] APU instead. For these, choose an [[FM2]] board for midrange desktop systems, or [[AM1]] for low-power systems with lightweight applications although please note that the AM1 currently lacks a functional IOMMU.

The 35W C32 4310EE and the 25W 3320EE are capable of 1Gbps routing and wireguard VPN on opnsense a FreeBSD distribution.

=== Building with AM3+ ===
{|class="wikitable" style="text-align:center;"
|+The Best AM3+ Processors by TDP
! rowspan="2" |Processor
! rowspan="2" |Cores
! colspan="3" |Frequency (GHz)
! rowspan="2" |TDP (W)
|-
!Base
!Full Load Turbo
!Half Load Turbo
|-
|Opteron 3320 EE
|4
|1.90
|2.10
|2.50
|25
|-
|Opteron 3350 HE
|4
|2.80
|3.10
|3.80
|45
|-
|Opteron 3380
|8
|2.60
|2.90
|3.60
|65
|-
|FX-4320
|4
|4.00
|4.10
|4.20
|95
|-
|FX-6330
|6
|3.60
|3.90
|4.20
|95
|-
|FX-8310
|8
|3.40
|3.70
|4.30
|95
|-
|FX-4350
|4
|4.20
|?
|4.30
|125
|-
|FX-8370
|8
|4.00
|4.10
|4.30
|125
|-
|FX-9590
|8
|4.70
|5.00
|5.00
|220
|}
''For all CPU models, see [[Socket AM3+#Orochi Processors]]''

[[Socket AM3+]] provides access to both the most power efficient and the most power hungry processors. [[coreboot-15h]] supports the [[Supermicro H8SML]] for efficient Opteron processors and the ASUS [[Sabertooth 990FX R2.0]] and [[Crosshair V Formula-Z]] motherboards for the fast FX processors. The FX-9590 can be TDP capped in [[coreboot-15h]] to use it as a very cold and efficient FX-8370 with higher turbo frequencies. For example, the TDP capped build [[orion]] runs a full core load at 4.00 GHz with core temperatures under 40°C (silently). Single core loads still reach 5.00 GHz in this setup.

[[Socket AM3+|AM3+]] is currently the best option for high single core performance on an open firmware system. For this reason, [[Socket AM3+|AM3+]] systems are preferred for latency sensitive tasks such as signal processing, web browsing, and gaming. By modern standards, it is possible to build a low to mid-tier gaming system using the [[Socket AM3+|AM3+]] platform. Recent games, such as Elden Ring, are able to run smoothly at 4K on [[orion]].

All [[Socket AM3+]] processors support ECC RAM and cache. Not all [[Socket AM3+]] motherboards wire the DDR3 ECC pins to the processor. The three [[Socket AM3+|AM3+]] motherboards supported by [[coreboot-15h]] all support ECC RAM. [[Socket AM3+]] only supports UDIMM memory, which limits the maximum supported memory for [[Socket AM3+|AM3+]] platforms.

As a consumer gaming platform, CPU coolers for [[Socket AM3+|AM3+]] are common and still widely-available. It is also easy to find compatible cases for the [[Socket AM3+|AM3+]] motherboards as they all use very common sizes. These aspects make [[Socket AM3+|AM3+]] systems very easy to build.

Unlike modern desktop CPUs (and other CPUs of its time), AM3+ is a PGA socket, with pins on the CPU and holes in the socket. Be careful to avoid bending pins on the CPU during installation and removal. The socket on the motherboard is typically harder to damage. Bent CPU pins are easily fixed using the empty tip of a mechanical pencil to reallign them.

<gallery>
File:CROSSHAIR ORION 261019.png|[[orion]]
File:Komos_sabertooth.png|[[komos]]
</gallery>

=== Building with C32 ===
{|class="wikitable" style="text-align:center;"
|+The Best C32 Processors by TDP
! rowspan="2" |Processor
! rowspan="2" |Cores
! colspan="3" |Frequency (GHz)
! rowspan="2" |TDP (W)
|-
!Base
!Full Load Turbo
!Half Load Turbo
|-
|Opteron 4310 EE
|4
|2.00
|
|3.00
|35
|-
|Opteron 4256 EE
|8
|1.60
|1.90
|2.80
|35
|-
|Opteron 42DX EE
|4
|2.20
|
|3.30
|40
|-
|Opteron 4365 EE
|8
|2.00
|2.30
|2.80
|40
|-
|Opteron 4332 HE
|6
|3.00
|3.30
|3.70
|65
|-
|Opteron 4376 HE
|8
|2.60
|2.90
|3.60
|65
|-
|Opteron 4340
|6
|3.50
|3.70
|3.80
|95
|-
|Opteron 4386
|8
|3.10
|3.40
|3.80
|95
|}
''For all CPU models, see [[Socket C32#Orochi Processors]]''

[[Socket C32]] motherboards covering both 1 and 2 socket configurations are supported. The fastest C32 CPU is the 8-core Opteron 4386, and UDIMM, RDIMM, and LRDIMM memory are all supported. Each CPU supports 2 memory channels, and all coreboot-15h-supported boards are 2-DIMM-per-channel. Unlike with G34, C32 CPUs support 64GB LRDIMMs in ''all'' slots - this means that, despite having half as many slots, C32 motherboards surprisingly support the same 256 GB per socket as G34, albeit with fewer channels.

C32 CPUs use LGA sockets, like Intel or newer AMD CPUs. This generally makes the CPU less fragile, but the socket on the motherboard more so.

As with modern PC hardware, if you purchase a C32 motherboard without CPUs installed, inspect its sockets closely for bent, damaged, or dirty pins.

Socket F 3.5 pitch coolers can be used for C32 and can be far more affordable and still available new, see the [[Coolers]] page for more information.

Early revisions of certain motherboards only support the 41xx CPU and must be avoided.

Most of the 2U server coolers are insufficient for the 95W C32 CPU's to be under 55C at low and quiet fan speeds when in use so it is advisable to obtain a 3U/4U case if you want it close to your desk.

<gallery>
File:KCMA-D8 ponos.png|[[ponos (2025)]]
File:H8SCM talos.png|[[talos (2025)]]
File:H8SCM komos.png|[[komos (2025)]]
</gallery>

=== Building with G34 ===
[[File:Qubesotron_2026.jpeg|thumb|[[Qubesotron]] - a build using the [[G34]] [[KGPE-D16]]]]
{|class="wikitable" style="text-align:center;"
|+The Best G34 Processors by TDP
! rowspan="2" |Processor
! rowspan="2" |Cores
! colspan="3" |Frequency (GHz)
! rowspan="2" |TDP (W)
|-
!Base
!Full Load Turbo
!Half Load Turbo
|-
|Opteron 6366 HE
|16
|1.80
|2.30
|3.10
|85
|-
|Opteron 6338P
|12
|2.30
|2.50
|2.80
|99
|-
|Opteron 6370P
|16
|2.00
|2.20
|2.50
|99
|-
|Opteron 6328
|8
|3.20
|3.50
|3.80
|115
|-
|Opteron 6380
|16
|2.50
|2.80
|3.40
|115
|-
|Opteron 6386 SE
|16
|2.80
|3.20
|3.50
|140
|}
''For all CPU models, see [[Socket G34#Orochi Processors]]''

[[Socket G34]], usually on the [[ASUS KGPE-D16]], is probably the most popular and best-known platform for FOSS firmware on AMD systems. G34 motherboards were made with 1, 2, and 4 sockets, and coreboot-15h supports boards covering all of these configurations. The fastest G34 CPU is the 16-core Opteron 6386 SE, and UDIMM, RDIMM, and LRDIMM memory are all supported. Each CPU supports 4 memory channels, and all coreboot-15h-supported boards are 2-DIMM-per-channel. RDIMMs up to 32GB, or LRDIMMs up to 64GB each, are both supported. Despite this, two 32GB RDIMMs can be used per channel, versus only one 64GB LRDIMM - this means that the memory limit is 256 GB per socket, whether you use RDIMM or LRDIMM memory. RDIMM is generally the fastest, least-expensive and most-compatible option.

Good G34 CPU coolers can be difficult to find - many G34 servers used passive CPU coolers reliant on specific fan and baffle arrangements, which are not easily adapted for standard PC cases in custom-built systems. A list of relevant CPU coolers is available on the [[Coolers]] page - the rare Noctua G34 coolers are well-regarded and highly-prized, while Dynatron active server coolers are sometimes still available used. Depending on what you can find, it may be easier to [[Cooler_Adapter|adapt a modern CPU cooler to fit]] instead.

G34 CPUs use LGA sockets, like Intel or newer AMD CPUs. This generally makes the CPU less fragile, but the socket on the motherboard more so.

As with modern PC hardware, if you purchase a G34 motherboard without CPUs installed, inspect its sockets closely for bent, damaged, or dirty pins and the CPU for damage to the components or contacts on the bottom.

There are several pre-built KGPE-D16 systems commonly available with low wear such as the Barracuda Opteron G34 which may be a good choice as they already come with the hard to find heatsinks and 16 core CPU's.

=== Building with AM1 ===
Platform currently has no IOMMU support

The [[ASRock AM1H-ITX]] motherboard was recently added to the [[coreboot-15h]] project. It is still in a testing phase. The [[ASUS AM1I-A]] is maintained by an external project.

=== Building with FM2 ===
'''TODO:''' Check for IOMMU support on FM2.

Two [[Socket FM2]] motherboards are supported by coreboot, but have not been thoroughly tested by the 15h community. These are the [[ASUS F2A85-M]] and [[ASUS A88XM-E]].

== PCI Express Devices ==
[[File:PM1725a.jpg|thumb|A Samsung PM1725a HHHL SSD - note the PCIe x8 card edge]]

The [[Family 15h]] and [[Family 16h]] platforms supported by coreboot-15h support up to PCI Express 2.0 ("Gen2") - a single Gen2 x16 slot delivers 8 GB/s of bandwidth. Compared to newer platforms, this can be a notable limitation for bandwidth-intensive devices such as GPUs or NVMe storage. For this reason, it's a good idea to select PCIe devices with more lanes whenever possible.

{| class="wikitable" style="text-align:left"
|+ PCI Express link performance
|- style="line-height:120%"
! scope="col" rowspan=2 | Version
! scope="col" rowspan=2 | Year introduced
! scope="col" rowspan=2 colspan=2 | Line code
! scope="col" rowspan=2 | Transfer rate<br>(per lane)
! scope="col" colspan=5 | Throughput (GB/s)
|-
! scope="col" | x1
! scope="col" | x2
! scope="col" | x4
! scope="col" | x8
! scope="col" | x16
|-
! scope="row" | 1.0
| 2003
| rowspan=5 | NRZ
| rowspan=2 | 8b/10b
| 2.5 GT/s
| {{shade|1.25|0.25|align=left}}
| {{shade|2.5|0.5|align=left}}
| {{shade|5|1|align=left}}
| {{shade|10|2|align=left}}
| {{shade|20|4|align=left}}
|-
! scope="row" | 2.0
| 2007
| 5.0 GT/s
| {{shade|2.5|0.5|align=left}}
| {{shade|5|1|align=left}}
| {{shade|10|2|align=left}}
| {{shade|20|4|align=left}}
| {{shade|40|8|align=left}}
|-
! scope="row" | 3.0
| 2010
| rowspan=3 | 128b/130b
| 8.0 GT/s
| {{shade|4.925|0.985|align=left}}
| {{shade|9.845|1.969|align=left}}
| {{shade|19.69|3.938|align=left}}
| {{shade|39.385|7.877|align=left}}
| {{shade|78.77|15.754|align=left}}
|-
! scope="row" | 4.0
| 2017
| 16.0 GT/s
| {{shade|9.485|1.969|align=left}}
| {{shade|19.69|3.938|align=left}}
| {{shade|39.385|7.877|align=left}}
| {{shade|78.77|15.754|align=left}}
| {{shade|157.54|31.508|align=left}}
|-
! scope="row" | 5.0
| 2019
| 32.0 GT/s
| {{shade|19.69|3.938|align=left}}
| {{shade|39.385|7.877|align=left}}
| {{shade|78.77|15.754|align=left}}
| {{shade|157.54|31.508|align=left}}
| {{shade|315.075|63.015|align=left}}
|}

This table shows the throughput of all PCIe lane widths, from Gen1 through Gen5. The advantages of additional PCIe lanes on a Gen2 chipset should be clear - a Gen2 x16 link provides comparable bandwidth to a Gen3 x8, or a Gen4 x4.

Extended PCI-e features such as Above 4G Decoding, Large/ReBAR, ARI and ATS are currently not supported by 15h coreboot but could potentially be added in the future as the chipset should support them.

PCI-e ACS is fully supported with the excellent IOMMU groups required by Qubes/Xen and VFIO device assignment.

SR-IOV is supported and should work fine under the limitations of not having ARI reducing the max VF's per bus.

=== Networking Cards ===
Almost any modern networking device should be compatible if it doesn't require large BAR support:

Most 15h workstation/server boards come with dual onboard Intel 82574L interfaces, since they do not feature an on-board flash chip they are safer for direct device assignment performed without the use of SR-IOV. Not assigning the ROM BAR to the guest may improve security for direct-attach.

It's recommended to use SR-IOV for safer device assignment and to lock the flash descriptors with intel ethernet tools if you're using a PCI-e network interface card in order to ensure maximum security.

'''TODO: How to lock PCI-e device flash descriptors on network cards, USB devices and so on.'''

'''1Gbps:'''

'''Intel i350:'''

This bridgeless and switchless PCI-e device with SR-IOV is available used and new in a variety of different configurations if you desire additional 1Gbps ports.

It is advised to use an intel firmware tool to ensure that WoL and iPXE/iSCSI is disabled on the re-writable ROM and the flash is disabled requiring a full system reboot to re-enable increasing the security level.

'''Broadcom BCM5719:'''

Considered a more free device than the i350 as substantially more logic is performed by the host loaded firmware instead of the card ROM. FOSS firmware has been developed for the RaptorCS Talos 2 LOM's which should also work in independent 5719 PCI-e cards for iPXE or BMC communication.

Removing the firmware from the card and locking the flash is considered best for security as the Linux drivers should provide general functionality without it and would likely make this the most secure option without the use of SR-IOV.

https://github.com/meklort/bcm5719-fw

https://github.com/meklort/bcm5719-fw/issues/232 (includes a list of card part numbers)

'''Intel 82576:'''

The quad port '''82576''' supports SR-IOV but it is a switched design and thus requires larger amounts of resources, their use could result in your graphics devices not receiving the proper BAR's. Security and flexibility is also reduced as each pair of ports shares an IOMMU group.

'''10Gbps:'''

(10/40 Cards without large BAR requirements, binary blobs and ideally no re-writable on-board firmware required for basic functionality should be listed here.)

TBD

'''25/40Gbps:'''

TBD

=== GPUs ===
Most high-end PCIe GPUs (old and new) support using all 16 lanes, but certain newer midrange cards are x8 or x4 and could potentially limit your 3D performance when limited to PCI-e 2.0

Newer cards will likely be highly CPU limited on the fastest available 15h CPU's.

'''''Recommended cards:'''''

AMD Polaris as the last generation of graphics cards without the vPSP, such as the Radeon RX590 8GB, the single slot Radeon Pro WX 7100 8GB or the low profile WX 4100.

Although the vPSP is restricted by the IOMMU and has nowhere near the level of access of it's mainboard counterparts it does prevent the theoretical development of owner controlled firmware for a video card which is already considered a very complex undertaking and will likely never happen.

If you do not care about that or consider the claim of the vPSP theoretically preventing hostile internal firmware re-writes as a benefit then potentially a newer x16 card could be purchased.

=== NVMe SSDs ===
[[File:M.2 Adapter.webp|thumb|A common generic M.2 adapter card kit. The bottom slot is for PCIe M.2 drives, the top slot (and cable) are for SATA M.2 drives.]]

Few motherboards supported by coreboot-15h have built-in M.2 slots. However, a PCIe M.2 SSD can be used in a PCIe slot using a common NVMe-to-x4 adapter card (many also allow an additional M.2 SATA SSD to be connected to a SATA port). A Gen2 x4 slot provides 2 GB/s of PCIe bandwidth - if your SSD's sequential read and write speeds are below 2000 MB/s, PCIe 2.0 will not bottleneck it. However, many NVMe SSDs are capable of more.

The D16 systems support PCI-e Bifurcation via the staging branch with two x16 slots capable of x8/x8 and configured in menuconfig thus making a four slot NVMe Cassette able to use two cards in position one and three.

It has yet to be added to the D8 but it should also work on this platform or any other with an electrical x16 slot.

Higher NVMe bandwidth on these platforms requires a directly attached SSD with more than 4 PCIe lanes - since the M.2 connector is only x4, this means using an AIC (Add-In Card)-format SSD, which installs directly in a PCIe slot. The following AIC SSDs are known to be capable of more than 2000 MB/s sequential throughput over at least 8 PCIe lanes:

{| class="wikitable sortable"
|+ Add-In Card SSD examples:
|-
! Model !! Capacity !! PCIe Width !! Sequential Read (MB/s) !! Sequential Write (MB/s) !! Random Read IOPS !! Random Write IOPS
|-
| Samsung PM1725a HHHL || 1.6/3.2/6.4 TB || x8 (up to Gen3) || 6200 (~3600 on Gen2) || 2600 || 1,000,000 || 180,000
|-
| Samsung PM1735a HHHL || 1.6/3.2/6.4/12.8 TB || x8 (up to Gen4) || 7000 (~3600 on Gen2) || 3200 || 800,000 || 135,000
|}
Another choice is a four slot switched NVMe PCI-e x16 card as this would enable the full usage of multiple modern PCI-e x4 SSD's with an oversubscribed PCI-e 2.0 x16 uplink if the switch supports lane rate conversion on the uplink. If you wish to assign NVMe devices to virtual machines one at a time and insure proper IOMMU groups and device isolation the switch must also support PCI-e ACS.

NVMe cassettes both switched and bifurcated can also be used to add other types of PCI-e M2 devices to a system with limited expansion slots.

Southbridge cards should work and are an excellent way to obtain modern features such as USB 3, SATA 6Gbps and additional PCI-e M2/NVMe slots.
== System Cooling ==
'''In order to ensure a long component life it is very important to ensure that your motherboard temperatures remain at optimal levels.'''

'''1U and 2U server cases use small loud fans and are unsuitable for deskside use with CPU's above 45W.'''

The primary heat sources on a motherboard that need cooling are the CPU, RAM, VRMs, Northbridge, Southbridge, and GPU. Internal sensors are used within the CPU to adjust fan speeds to maintain safe CPU temperatures. Many processors can be configured to throttle if the CPU die is becoming unsafely hot as a secondary protection mechanism. Dedicated GPU cards often operate the same way. The remaining components (RAM, VRMs, Northbridge, and Southbridge) all expect to be sufficiently cooled by case airflow. This is where differences between "Desktop" and "Server" motherboards become important.

[[File:Desktop vs Server.png|border|600px|A visual comparison of Desktop (left) and Server (right) motherboard cooling expectations.]]
[[File:Server air shroud.png|border|375px|A server air shroud condenses and focuses airflow over key components.]]

Server boards are designed for small cases with loud, powerful fans. Air shrouds are frequently utilized to further condense air over key components. Desktop boards often have larger heatsinks on the VRMs, Northbridge, and Southbridge to allow for quieter, less powerful fans in an office environment. A pair of motherboards with similar components is shown above to highlight the differences between Desktop and Server designs. The Server motherboard has significantly less cooling on the VRMs and no heatsink at all on the Southbridge.

Even larger Server boards, such as the [[KGPE-D16]], can be found with '''no VRM cooling''' despite housing more powerful processors than the two boards shown above.

Desktop systems largely place the motherboard perpendicular to the ground, allowing hot air to naturally flow towards the "top" of the motherboard. Heatsink fins and RAM are oriented to utilize this passive heat convection. Servers largely orient the motherboard parallel to the ground and expect "front to back" airflow in the case. Installing a Server motherboard in a vertical Desktop case can cause cooling problems for the installed RAM; the RAM modules will be stacked above each other, forcing the "topmost" module to absorb a tremendous amount of heat from the modules beneath it.

The "topmost" module in a fully populated, vertically oriented Server motherboard can thus rapidly exceed 120°C under load without sufficient cooling.

[[File:Supermicro Workstation.png|border|375px]]

Workstation systems utilize Server motherboards in a vertical case, similar to Desktops. Powerful fans are placed along the edge of the motherboard, housed in green in the above example, to provide concentrated "front to back" airflow over the motherboard. If you are building a Workstation, it is best to choose a tight fitting case with high pressure fans positioned close to the motherboard.

'''TODO:'''

Northbridge fan cooling example.

Cooling the northbridge chipset when using a graphics card or other PCI-e device that extends over it (almost all of them) and optimal temperatures for component life.

== Shopping Tips ==

It is recommended to purchase later revision boards without visible dust buildup as they will likely be in better condition.

== Configuration and Tuning ==
'''Power Conservation:'''

Compile all PCI-e power saving options and force enable ASPM for all devices in your operating system in order to reduce CPU wakeup.

Use nohz=on and nohz full kernel command line options for a tickless system.

CPU Governor ondemand or conservative.

Disabling WoL with ethtool on each interface will shut off the network interfaces when the system is off and save a few watts of power, WoL is why the LOM status lights are on when the system is plugged in.

Using the jumpers to disable unneeded on board devices such as VGA or the LOM's since the 82574L has ASPM disabled in the e1000e driver and the VGA doesn't work at all without a blob on the Supermicro motherboards.

'''Security:'''

Microcode updates are highly recommended in order to provide secure operation of the Piledriver IOMMU, fix CPU timing errors and provide Spectre related enhancements.

Orion

2026-10-21T09:29:30Z

Mrothfuss:

{{Infobox individual system
|image = CROSSHAIR ORION 261019.png
|image_size = 300
|caption = An inside view of orion

|name = orion
|owner = [[User:mrothfuss|mrothfuss]]
|built = 2026

|motherboard = [[Crosshair V Formula-Z]]
|cpu = 1x FX-9590
|ram = 32GB (1866 MHz UDIMM ECC)
|gpu = RX 5600 XT
|storage1 = 2x 500GB SATA SSD
|storage2 = 2x 500GB NVMe SSD
|storage3 = 1x 1TB NVMe SSD
|psu = 750W (Seasonic)
|chassis = QUBE 540
|cooler = upHere UE2K6

|firmware = [[coreboot-15h]] staging
|payload = SeaBIOS
|oproms = dGPU
|os = RABID FreeBSD
|filesystem = ZFS
|workload = Workstation
}}

'''orion''' is [[User:mrothfuss|mrothfuss]]'s silent workstation. A custom 3D printed mount was used to add a fan below the PSU. One x16 PCIe slot is bifurcated into two x8 slots to support two x4 NVMe SSDs.

It is setup to dual-boot Debian to run proprietary software (steam).

File:Kgpe-d16.jpeg

2026-10-20T11:51:49Z

Mrothfuss: Mrothfuss uploaded a new version of File:Kgpe-d16.jpeg

Build Guide

2026-10-20T08:41:48Z

Mrothfuss: ditch colons for consistent headings

[[File:Komos_sabertooth.png|thumb|[[Komos]] - a build using the [[AM3+]] [[Sabertooth 990FX R2.0]]]]
Since you're reading the 15h.org build guide, we'll assume you're interested in building a fully-FOSS-firmware-compatible AMD system to run [[coreboot-15h]]. This guide assumes you're looking to build a new desktop, server, or workstation system from separately-purchased components.

If you are ''not'' building from separate components (such as for the various prebuilt [[Supermicro]] servers which included compatible motherboards), head over to the [[Motherboards]] page and look for your board's model. For laptops, see the [[Laptops]] page.

== Choosing a Platform ==
coreboot-15h is available for many motherboards, across several different AMD sockets - which one you should choose depends on the balance of performance, cost, power consumption, and physical size you want for your system.

For an easy to build open source desktop, the [[Build Guide#Building with AM3+|AM3+]] platform is recommended. Compatible cases and [[Coolers|CPU coolers]] are easy to find. [[Build Guide#Building with AM3+|AM3+]] processors have the highest single core performance, making them the best choice for responsive activities such as web browsing or gaming.

Users that require lots of RAM (1024 GB max) or many cores (64 max) should look at the [[Build Guide#Building with C32|C32]] and [[Build Guide#Building with G34|G34]] platforms. The [[Build Guide#Building with C32|C32]] is the smaller of the two and is easier to build: motherboards can fit common cases and compatible [[Coolers|CPU coolers]] are easy to find. A more powerful system can be built with [[Build Guide#Building with G34|G34]], but compatible cases and coolers can be hard to find.

Small (mITX to uATX), low power (25 to 40 W) open source machines can be built using the [[Build Guide#Building with AM1|AM1]], [[Build Guide#Building with AM3+|AM3+]], and [[Build Guide#Building with C32|C32]] platforms.

Many of the supported platforms can use ECC memory and have a working IOMMU. ECC memory support is important for machines running nonstop over long periods of time. The IOMMU enables PCIe device isolation or passthrough to a virtual machine.

'''Qubes:'''

While most of the systems besides the AM1 fit all the requirements only the KGPE-D16 supports a TPM 2.0 module.

('''TODO:''' Check Supermicro systems for TPM support and see if it works without the VGA/BMC blob)

There is currently a cpupower bug in Xen and since qubes doesn't auto-pin cores the CPU won't throttle and idle properly so single lower wattage CPU's are recommended.

{|class="wikitable" style="text-align:center;"
|+
! rowspan="2" |Socket Type
! colspan="4" |Motherboard
! colspan="4" |Per Socket
! rowspan="2" |ECC Support
! rowspan="2" |IOMMU Support
|-
!Size
!CPU Sockets
!Model
!Type
!CPU Cores
!Max Frequency (GHz)
!CPU TDP (W)
!Max RAM
|-
|[[Build Guide#Building with AM1|Socket AM1]]
|mITX
|1
|[[ASRock AM1H-ITX]]
|Desktop
|2 to 4
|2.20
|25
|16 GB
|Yes
|No
|-
| rowspan="3" |[[Build Guide#Building with AM3+|Socket AM3+]]
|uATX
| rowspan="3" |1
|[[Supermicro H8SML]]
|Server
| rowspan="3" |4 to 8
|3.80
|25 to 65
| rowspan="3" |64 GB
| rowspan="3" |Yes
| rowspan="3" |Yes
|-
| rowspan="2" |ATX
|[[ASUS Crosshair V Formula-Z]]
| rowspan="2" |Desktop
| rowspan="2" |5.00
| rowspan="2" |25 to 220
|-
|[[ASUS Sabertooth 990FX R2.0]]
|-
| rowspan="2" |[[Build Guide#Building with C32|Socket C32]]
|uATX
|1
|[[Supermicro H8SCM]]
| rowspan="2" |Server
| rowspan="2" |4 to 8
| rowspan="2" |3.80
| rowspan="2" |35 to 95
| rowspan="2" |256 GB
| rowspan="2" |Yes
| rowspan="2" |Yes
|-
|SSI CEB
|2
|[[ASUS KCMA-D8]]
|-
| rowspan="3" |[[Build Guide#Building with G34|Socket G34]]
|ATX
|1
|[[Supermicro H8SGL]]
| rowspan="3" |Server
| rowspan="3" |4 to 16
| rowspan="3" |3.80
| rowspan="3" |85 to 140
| rowspan="3" |256 GB
| rowspan="3" |Yes
| rowspan="3" |Yes
|-
|SSI EEB
|2
|[[ASUS KGPE-D16]]
|-
|SWTX
|4
|[[Supermicro H8QG6]]
|}

All of these platforms besides the AM1 support ECC memory, IOMMU, SR-IOV, SLAT, PCI-e ACS and are based on [[Orochi]] - AMD's high-power, high-performance platform for [[Family 15h]] systems.

If you're looking to build a lower-power quad-core system (such as for an efficient router or media player machine), you may be interested in a [[Trinity|Trinity/Richland]] or [[Kabini]] APU instead. For these, choose an [[FM2]] board for midrange desktop systems, or [[AM1]] for low-power systems with lightweight applications although please note that the AM1 currently lacks a functional IOMMU.

The 35W C32 4310EE and the 25W 3320EE are capable of 1Gbps routing and wireguard VPN on opnsense a FreeBSD distribution.

=== Building with AM3+ ===
{|class="wikitable" style="text-align:center;"
|+The Best AM3+ Processors by TDP
! rowspan="2" |Processor
! rowspan="2" |Cores
! colspan="3" |Frequency (GHz)
! rowspan="2" |TDP (W)
|-
!Base
!Full Load Turbo
!Half Load Turbo
|-
|Opteron 3320 EE
|4
|1.90
|2.10
|2.50
|25
|-
|Opteron 3350 HE
|4
|2.80
|3.10
|3.80
|45
|-
|Opteron 3380
|8
|2.60
|2.90
|3.60
|65
|-
|FX-4320
|4
|4.00
|4.10
|4.20
|95
|-
|FX-6330
|6
|3.60
|3.90
|4.20
|95
|-
|FX-8310
|8
|3.40
|3.70
|4.30
|95
|-
|FX-4350
|4
|4.20
|?
|4.30
|125
|-
|FX-8370
|8
|4.00
|4.10
|4.30
|125
|-
|FX-9590
|8
|4.70
|5.00
|5.00
|220
|}
''For all CPU models, see [[Socket AM3+#Orochi Processors]]''

coreboot-15h supports [[Socket AM3+]] on the ASUS [[Sabertooth 990FX R2.0]] and [[Crosshair V Formula-Z]]. The fastest AM3+ is the 8-core FX-9590. This platform uses DDR3 UDIMM (ordinary desktop RAM) in the usual dual-channel, 2-DIMM-per-channel configuration, and also optionally supports (UDIMM) ECC memory - DIMMs up to 16GB each are supported, for up to 64GB total.

As a consumer gaming platform, CPU coolers for AM3+ are common and still widely-available.

Unlike modern desktop CPUs (and other CPUs of its time), AM3+ is PGA socket, with pins on the CPU and holes in the socket. Be careful to avoid bending pins on the CPU during installation and removal. The socket on the motherboard is typically harder to damage.

AM3+ is currently the best option if you desire a comparatively fast libre firmware system for playing your proprietary games or 3D applications.

Although you will likely and should only be using these systems only for secure computing it's technically possible to play popular critically acclaimed semi-modern games such as Baulders Gate 3, Dishonored 2, Deus Ex: Mankind Divided and Cyberpunk 2077 at reasonably acceptable frame-rates, and several users have had coreboot 15h platforms as their primary gaming PC for the past decade.

Due to the low per core speeds only highly multi-threaded games will work well and the lack of those around the release of the AMD FX was why they were received so poorly yet have held up substantially better than Intel platforms of the same generation.

<gallery>
File:CROSSHAIR ORION 261019.png|[[orion]]
File:Komos_sabertooth.png|[[komos]]
</gallery>

=== Building with C32 ===
{|class="wikitable" style="text-align:center;"
|+The Best C32 Processors by TDP
! rowspan="2" |Processor
! rowspan="2" |Cores
! colspan="3" |Frequency (GHz)
! rowspan="2" |TDP (W)
|-
!Base
!Full Load Turbo
!Half Load Turbo
|-
|Opteron 4310 EE
|4
|2.00
|
|3.00
|35
|-
|Opteron 4256 EE
|8
|1.60
|1.90
|2.80
|35
|-
|Opteron 42DX EE
|4
|2.20
|
|3.30
|40
|-
|Opteron 4365 EE
|8
|2.00
|2.30
|2.80
|40
|-
|Opteron 4332 HE
|6
|3.00
|3.30
|3.70
|65
|-
|Opteron 4376 HE
|8
|2.60
|2.90
|3.60
|65
|-
|Opteron 4340
|6
|3.50
|3.70
|3.80
|95
|-
|Opteron 4386
|8
|3.10
|3.40
|3.80
|95
|}
''For all CPU models, see [[Socket C32#Orochi Processors]]''

[[Socket C32]] motherboards covering both 1 and 2 socket configurations are supported. The fastest C32 CPU is the 8-core Opteron 4386, and UDIMM, RDIMM, and LRDIMM memory are all supported. Each CPU supports 2 memory channels, and all coreboot-15h-supported boards are 2-DIMM-per-channel. Unlike with G34, C32 CPUs support 64GB LRDIMMs in ''all'' slots - this means that, despite having half as many slots, C32 motherboards surprisingly support the same 256 GB per socket as G34, albeit with fewer channels.

C32 CPUs use LGA sockets, like Intel or newer AMD CPUs. This generally makes the CPU less fragile, but the socket on the motherboard more so.

As with modern PC hardware, if you purchase a C32 motherboard without CPUs installed, inspect its sockets closely for bent, damaged, or dirty pins.

Socket F 3.5 pitch coolers can be used for C32 and can be far more affordable and still available new, see the [[Coolers]] page for more information.

Early revisions of certain motherboards only support the 41xx CPU and must be avoided.

Most of the 2U server coolers are insufficient for the 95W C32 CPU's to be under 55C at low and quiet fan speeds when in use so it is advisable to obtain a 3U/4U case if you want it close to your desk.

<gallery>
File:KCMA-D8 ponos.png|[[ponos (2025)]]
File:H8SCM talos.png|[[talos (2025)]]
File:H8SCM komos.png|[[komos (2025)]]
</gallery>

=== Building with G34 ===
[[File:Qubesotron_2026.jpeg|thumb|[[Qubesotron]] - a build using the [[G34]] [[KGPE-D16]]]]
{|class="wikitable" style="text-align:center;"
|+The Best G34 Processors by TDP
! rowspan="2" |Processor
! rowspan="2" |Cores
! colspan="3" |Frequency (GHz)
! rowspan="2" |TDP (W)
|-
!Base
!Full Load Turbo
!Half Load Turbo
|-
|Opteron 6366 HE
|16
|1.80
|2.30
|3.10
|85
|-
|Opteron 6338P
|12
|2.30
|2.50
|2.80
|99
|-
|Opteron 6370P
|16
|2.00
|2.20
|2.50
|99
|-
|Opteron 6328
|8
|3.20
|3.50
|3.80
|115
|-
|Opteron 6380
|16
|2.50
|2.80
|3.40
|115
|-
|Opteron 6386 SE
|16
|2.80
|3.20
|3.50
|140
|}
''For all CPU models, see [[Socket G34#Orochi Processors]]''

[[Socket G34]], usually on the [[ASUS KGPE-D16]], is probably the most popular and best-known platform for FOSS firmware on AMD systems. G34 motherboards were made with 1, 2, and 4 sockets, and coreboot-15h supports boards covering all of these configurations. The fastest G34 CPU is the 16-core Opteron 6386 SE, and UDIMM, RDIMM, and LRDIMM memory are all supported. Each CPU supports 4 memory channels, and all coreboot-15h-supported boards are 2-DIMM-per-channel. RDIMMs up to 32GB, or LRDIMMs up to 64GB each, are both supported. Despite this, two 32GB RDIMMs can be used per channel, versus only one 64GB LRDIMM - this means that the memory limit is 256 GB per socket, whether you use RDIMM or LRDIMM memory. RDIMM is generally the fastest, least-expensive and most-compatible option.

Good G34 CPU coolers can be difficult to find - many G34 servers used passive CPU coolers reliant on specific fan and baffle arrangements, which are not easily adapted for standard PC cases in custom-built systems. A list of relevant CPU coolers is available on the [[Coolers]] page - the rare Noctua G34 coolers are well-regarded and highly-prized, while Dynatron active server coolers are sometimes still available used. Depending on what you can find, it may be easier to [[Cooler_Adapter|adapt a modern CPU cooler to fit]] instead.

G34 CPUs use LGA sockets, like Intel or newer AMD CPUs. This generally makes the CPU less fragile, but the socket on the motherboard more so.

As with modern PC hardware, if you purchase a G34 motherboard without CPUs installed, inspect its sockets closely for bent, damaged, or dirty pins and the CPU for damage to the components or contacts on the bottom.

There are several pre-built KGPE-D16 systems commonly available with low wear such as the Barracuda Opteron G34 which may be a good choice as they already come with the hard to find heatsinks and 16 core CPU's.

=== Building with AM1 ===
Platform currently has no IOMMU support

The [[ASRock AM1H-ITX]] motherboard was recently added to the [[coreboot-15h]] project. It is still in a testing phase. The [[ASUS AM1I-A]] is maintained by an external project.

=== Building with FM2 ===
'''TODO:''' Check for IOMMU support on FM2.

Two [[Socket FM2]] motherboards are supported by coreboot, but have not been thoroughly tested by the 15h community. These are the [[ASUS F2A85-M]] and [[ASUS A88XM-E]].

== PCI Express Devices ==
[[File:PM1725a.jpg|thumb|A Samsung PM1725a HHHL SSD - note the PCIe x8 card edge]]

The [[Family 15h]] and [[Family 16h]] platforms supported by coreboot-15h support up to PCI Express 2.0 ("Gen2") - a single Gen2 x16 slot delivers 8 GB/s of bandwidth. Compared to newer platforms, this can be a notable limitation for bandwidth-intensive devices such as GPUs or NVMe storage. For this reason, it's a good idea to select PCIe devices with more lanes whenever possible.

{| class="wikitable" style="text-align:left"
|+ PCI Express link performance
|- style="line-height:120%"
! scope="col" rowspan=2 | Version
! scope="col" rowspan=2 | Year introduced
! scope="col" rowspan=2 colspan=2 | Line code
! scope="col" rowspan=2 | Transfer rate<br>(per lane)
! scope="col" colspan=5 | Throughput (GB/s)
|-
! scope="col" | x1
! scope="col" | x2
! scope="col" | x4
! scope="col" | x8
! scope="col" | x16
|-
! scope="row" | 1.0
| 2003
| rowspan=5 | NRZ
| rowspan=2 | 8b/10b
| 2.5 GT/s
| {{shade|1.25|0.25|align=left}}
| {{shade|2.5|0.5|align=left}}
| {{shade|5|1|align=left}}
| {{shade|10|2|align=left}}
| {{shade|20|4|align=left}}
|-
! scope="row" | 2.0
| 2007
| 5.0 GT/s
| {{shade|2.5|0.5|align=left}}
| {{shade|5|1|align=left}}
| {{shade|10|2|align=left}}
| {{shade|20|4|align=left}}
| {{shade|40|8|align=left}}
|-
! scope="row" | 3.0
| 2010
| rowspan=3 | 128b/130b
| 8.0 GT/s
| {{shade|4.925|0.985|align=left}}
| {{shade|9.845|1.969|align=left}}
| {{shade|19.69|3.938|align=left}}
| {{shade|39.385|7.877|align=left}}
| {{shade|78.77|15.754|align=left}}
|-
! scope="row" | 4.0
| 2017
| 16.0 GT/s
| {{shade|9.485|1.969|align=left}}
| {{shade|19.69|3.938|align=left}}
| {{shade|39.385|7.877|align=left}}
| {{shade|78.77|15.754|align=left}}
| {{shade|157.54|31.508|align=left}}
|-
! scope="row" | 5.0
| 2019
| 32.0 GT/s
| {{shade|19.69|3.938|align=left}}
| {{shade|39.385|7.877|align=left}}
| {{shade|78.77|15.754|align=left}}
| {{shade|157.54|31.508|align=left}}
| {{shade|315.075|63.015|align=left}}
|}

This table shows the throughput of all PCIe lane widths, from Gen1 through Gen5. The advantages of additional PCIe lanes on a Gen2 chipset should be clear - a Gen2 x16 link provides comparable bandwidth to a Gen3 x8, or a Gen4 x4.

Extended PCI-e features such as Above 4G Decoding, Large/ReBAR, ARI and ATS are currently not supported by 15h coreboot but could potentially be added in the future as the chipset should support them.

PCI-e ACS is fully supported with the excellent IOMMU groups required by Qubes/Xen and VFIO device assignment.

SR-IOV is supported and should work fine under the limitations of not having ARI reducing the max VF's per bus.

=== Networking Cards ===
Almost any modern networking device should be compatible if it doesn't require large BAR support:

Most 15h workstation/server boards come with dual onboard Intel 82574L interfaces, since they do not feature an on-board flash chip they are safer for direct device assignment performed without the use of SR-IOV. Not assigning the ROM BAR to the guest may improve security for direct-attach.

It's recommended to use SR-IOV for safer device assignment and to lock the flash descriptors with intel ethernet tools if you're using a PCI-e network interface card in order to ensure maximum security.

'''TODO: How to lock PCI-e device flash descriptors on network cards, USB devices and so on.'''

'''1Gbps:'''

'''Intel i350:'''

This bridgeless and switchless PCI-e device with SR-IOV is available used and new in a variety of different configurations if you desire additional 1Gbps ports.

It is advised to use an intel firmware tool to ensure that WoL and iPXE/iSCSI is disabled on the re-writable ROM and the flash is disabled requiring a full system reboot to re-enable increasing the security level.

'''Broadcom BCM5719:'''

Considered a more free device than the i350 as substantially more logic is performed by the host loaded firmware instead of the card ROM. FOSS firmware has been developed for the RaptorCS Talos 2 LOM's which should also work in independent 5719 PCI-e cards for iPXE or BMC communication.

Removing the firmware from the card and locking the flash is considered best for security as the Linux drivers should provide general functionality without it and would likely make this the most secure option without the use of SR-IOV.

https://github.com/meklort/bcm5719-fw

https://github.com/meklort/bcm5719-fw/issues/232 (includes a list of card part numbers)

'''Intel 82576:'''

The quad port '''82576''' supports SR-IOV but it is a switched design and thus requires larger amounts of resources, their use could result in your graphics devices not receiving the proper BAR's. Security and flexibility is also reduced as each pair of ports shares an IOMMU group.

'''10Gbps:'''

(10/40 Cards without large BAR requirements, binary blobs and ideally no re-writable on-board firmware required for basic functionality should be listed here.)

TBD

'''25/40Gbps:'''

TBD

=== GPUs ===
Most high-end PCIe GPUs (old and new) support using all 16 lanes, but certain newer midrange cards are x8 or x4 and could potentially limit your 3D performance when limited to PCI-e 2.0

Newer cards will likely be highly CPU limited on the fastest available 15h CPU's.

'''''Recommended cards:'''''

AMD Polaris as the last generation of graphics cards without the vPSP, such as the Radeon RX590 8GB, the single slot Radeon Pro WX 7100 8GB or the low profile WX 4100.

Although the vPSP is restricted by the IOMMU and has nowhere near the level of access of it's mainboard counterparts it does prevent the theoretical development of owner controlled firmware for a video card which is already considered a very complex undertaking and will likely never happen.

If you do not care about that or consider the claim of the vPSP theoretically preventing hostile internal firmware re-writes as a benefit then potentially a newer x16 card could be purchased.

=== NVMe SSDs ===
[[File:M.2 Adapter.webp|thumb|A common generic M.2 adapter card kit. The bottom slot is for PCIe M.2 drives, the top slot (and cable) are for SATA M.2 drives.]]

Few motherboards supported by coreboot-15h have built-in M.2 slots. However, a PCIe M.2 SSD can be used in a PCIe slot using a common NVMe-to-x4 adapter card (many also allow an additional M.2 SATA SSD to be connected to a SATA port). A Gen2 x4 slot provides 2 GB/s of PCIe bandwidth - if your SSD's sequential read and write speeds are below 2000 MB/s, PCIe 2.0 will not bottleneck it. However, many NVMe SSDs are capable of more.

The D16 systems support PCI-e Bifurcation via the staging branch with two x16 slots capable of x8/x8 and configured in menuconfig thus making a four slot NVMe Cassette able to use two cards in position one and three.

It has yet to be added to the D8 but it should also work on this platform or any other with an electrical x16 slot.

Higher NVMe bandwidth on these platforms requires a directly attached SSD with more than 4 PCIe lanes - since the M.2 connector is only x4, this means using an AIC (Add-In Card)-format SSD, which installs directly in a PCIe slot. The following AIC SSDs are known to be capable of more than 2000 MB/s sequential throughput over at least 8 PCIe lanes:

{| class="wikitable sortable"
|+ Add-In Card SSD examples:
|-
! Model !! Capacity !! PCIe Width !! Sequential Read (MB/s) !! Sequential Write (MB/s) !! Random Read IOPS !! Random Write IOPS
|-
| Samsung PM1725a HHHL || 1.6/3.2/6.4 TB || x8 (up to Gen3) || 6200 (~3600 on Gen2) || 2600 || 1,000,000 || 180,000
|-
| Samsung PM1735a HHHL || 1.6/3.2/6.4/12.8 TB || x8 (up to Gen4) || 7000 (~3600 on Gen2) || 3200 || 800,000 || 135,000
|}
Another choice is a four slot switched NVMe PCI-e x16 card as this would enable the full usage of multiple modern PCI-e x4 SSD's with an oversubscribed PCI-e 2.0 x16 uplink if the switch supports lane rate conversion on the uplink. If you wish to assign NVMe devices to virtual machines one at a time and insure proper IOMMU groups and device isolation the switch must also support PCI-e ACS.

NVMe cassettes both switched and bifurcated can also be used to add other types of PCI-e M2 devices to a system with limited expansion slots.

Southbridge cards should work and are an excellent way to obtain modern features such as USB 3, SATA 6Gbps and additional PCI-e M2/NVMe slots.
== System Cooling ==
'''In order to ensure a long component life it is very important to ensure that your motherboard temperatures remain at optimal levels.'''

'''1U and 2U server cases use small loud fans and are unsuitable for deskside use with CPU's above 45W.'''

The primary heat sources on a motherboard that need cooling are the CPU, RAM, VRMs, Northbridge, Southbridge, and GPU. Internal sensors are used within the CPU to adjust fan speeds to maintain safe CPU temperatures. Many processors can be configured to throttle if the CPU die is becoming unsafely hot as a secondary protection mechanism. Dedicated GPU cards often operate the same way. The remaining components (RAM, VRMs, Northbridge, and Southbridge) all expect to be sufficiently cooled by case airflow. This is where differences between "Desktop" and "Server" motherboards become important.

[[File:Desktop vs Server.png|border|600px|A visual comparison of Desktop (left) and Server (right) motherboard cooling expectations.]]
[[File:Server air shroud.png|border|375px|A server air shroud condenses and focuses airflow over key components.]]

Server boards are designed for small cases with loud, powerful fans. Air shrouds are frequently utilized to further condense air over key components. Desktop boards often have larger heatsinks on the VRMs, Northbridge, and Southbridge to allow for quieter, less powerful fans in an office environment. A pair of motherboards with similar components is shown above to highlight the differences between Desktop and Server designs. The Server motherboard has significantly less cooling on the VRMs and no heatsink at all on the Southbridge.

Even larger Server boards, such as the [[KGPE-D16]], can be found with '''no VRM cooling''' despite housing more powerful processors than the two boards shown above.

Desktop systems largely place the motherboard perpendicular to the ground, allowing hot air to naturally flow towards the "top" of the motherboard. Heatsink fins and RAM are oriented to utilize this passive heat convection. Servers largely orient the motherboard parallel to the ground and expect "front to back" airflow in the case. Installing a Server motherboard in a vertical Desktop case can cause cooling problems for the installed RAM; the RAM modules will be stacked above each other, forcing the "topmost" module to absorb a tremendous amount of heat from the modules beneath it.

The "topmost" module in a fully populated, vertically oriented Server motherboard can thus rapidly exceed 120°C under load without sufficient cooling.

[[File:Supermicro Workstation.png|border|375px]]

Workstation systems utilize Server motherboards in a vertical case, similar to Desktops. Powerful fans are placed along the edge of the motherboard, housed in green in the above example, to provide concentrated "front to back" airflow over the motherboard. If you are building a Workstation, it is best to choose a tight fitting case with high pressure fans positioned close to the motherboard.

'''TODO:'''

Northbridge fan cooling example.

Cooling the northbridge chipset when using a graphics card or other PCI-e device that extends over it (almost all of them) and optimal temperatures for component life.

== Shopping Tips ==

It is recommended to purchase later revision boards without visible dust buildup as they will likely be in better condition.

== Configuration and Tuning ==
'''Power Conservation:'''

Compile all PCI-e power saving options and force enable ASPM for all devices in your operating system in order to reduce CPU wakeup.

Use nohz=on and nohz full kernel command line options for a tickless system.

CPU Governor ondemand or conservative.

Disabling WoL with ethtool on each interface will shut off the network interfaces when the system is off and save a few watts of power, WoL is why the LOM status lights are on when the system is plugged in.

Using the jumpers to disable unneeded on board devices such as VGA or the LOM's since the 82574L has ASPM disabled in the e1000e driver and the VGA doesn't work at all without a blob on the Supermicro motherboards.

'''Security:'''

Microcode updates are highly recommended in order to provide secure operation of the Piledriver IOMMU, fix CPU timing errors and provide Spectre related enhancements.

Supermicro H8SGL

2026-10-19T20:36:28Z

Mrothfuss:

{{Infobox motherboard
|image = H8SGL Board.png
|image_size = 300

|introduced = 2010
|manufacturer = [[SuperMicro]]

|socket = 1x [[G34]]
|northbridge = [[AMD SR5650]]
|southbridge = [[AMD SP5100]]
|superio = [[Winbond W83527HG]]
|bmc = [[Nuvoton WPCM450]]
|bmcflash = Onboard
|ram = 8 slots (4 channels) DDR3-1600 ECC UDIMM/RDIMM/LRDIMM, up to 256GB
|bios = 2 MiB soldered SOIC-8 (W25Q16V)
|formfactor = ATX
|power = 1x 8-pin EPS

|slot1 = PCIe Gen2 x16 (electrically x8)
|slot2 = PCIe Gen2 x8
|slot3 = PCIe Gen2 x8 (electrically x4)
|slot4 = 32-bit Legacy PCI

|gpu = Matrox G200eW
|nic = 2x Intel 82574L Gigabit
|storagecontroller = SP5100's SATA2 (3.0 Gbps)
|usbcontroller = SP5100's onboard USB 2.0
|serial = One external, one internal
|audio = None
}}

The H8SGL motherboard is highly supported by [[coreboot-15h]].

== Open Source Firmware ==
Open source firmware for the H8SGL is provided by [[coreboot-15h]] utilizing AMD's open source AGESA and CIMx releases for platform initialization.

=== coreboot-15h ===
{{Excerpt|Coreboot-15h|[[Supermicro H8SGL]]|hat=no|bold=1}}

=== Missing Features ===
* SeaBIOS does not respond to keyboards behind a USB hub.
* Hibernation and Suspend/Resume are unsupported.
* Opteron 6100 series CPUs are unsupported.
* The two serial ports do not work while the BMC is offline.

=== Flashing ===
To switch from the stock firmware to coreboot, [[External Flashing | external flashing]] is required. The flash chip is located between PCI slots 2 and 3, near the SP5100.

== Deployed Systems ==
* [[ponos]]

== Motherboard Diagrams ==
[[File:H8SGL Diagram.png|frameless|400x400px]]
[[File:H8SGL BlockDiagram.png|frameless|400x400px]]

The SP5100 is incorrectly labeled "SR5100" in the board diagram.

== Motherboard Components ==
=== Socket G34 ===
{{Excerpt|Socket G34|inline=yes|bold=yes}}
==== AMD Opteron 6100 Series ====
{{Excerpt|Socket G34#K10 Processors|inline=yes|bold=yes}}
==== AMD Opteron 6200 and 6300 Series ====
{{Excerpt|Socket G34#Orochi Processors|inline=yes|bold=yes}}

=== AMD SR5650 ===
{{Excerpt|AMD SR5650|inline=yes|bold=yes}}
=== AMD SP5100 ===
{{Excerpt|AMD SP5100|inline=yes|bold=yes}}
=== Winbond W83527HG ===
{{Excerpt|Winbond W83527HG|hat=no}}
=== Nuvoton W83795G ===
{{Excerpt|Nuvoton W83795G/ADG|hat=no}}
=== Nuvoton WPCM450 ===
{{Excerpt|Nuvoton WPCM450|hat=no}}

== References ==

Build Guide

2026-10-19T20:03:52Z

Mrothfuss: /* Building with G34 */

[[File:Komos_sabertooth.png|thumb|[[Komos]] - a build using the [[AM3+]] [[Sabertooth 990FX R2.0]]]]
Since you're reading the 15h.org build guide, we'll assume you're interested in building a fully-FOSS-firmware-compatible AMD system to run [[coreboot-15h]]. This guide assumes you're looking to build a new desktop, server, or workstation system from separately-purchased components.

If you are ''not'' building from separate components (such as for the various prebuilt [[Supermicro]] servers which included compatible motherboards), head over to the [[Motherboards]] page and look for your board's model. For laptops, see the [[Laptops]] page.

== Choosing a Platform ==
coreboot-15h is available for many motherboards, across several different AMD sockets - which one you should choose depends on the balance of performance, cost, power consumption, and physical size you want for your system.

For an easy to build open source desktop, the [[Build Guide#Building with AM3+|AM3+]] platform is recommended. Compatible cases and [[Coolers|CPU coolers]] are easy to find. [[Build Guide#Building with AM3+|AM3+]] processors have the highest single core performance, making them the best choice for responsive activities such as web browsing or gaming.

Users that require lots of RAM (1024 GB max) or many cores (64 max) should look at the [[Build Guide#Building with C32|C32]] and [[Build Guide#Building with G34|G34]] platforms. The [[Build Guide#Building with C32|C32]] is the smaller of the two and is easier to build: motherboards can fit common cases and compatible [[Coolers|CPU coolers]] are easy to find. A more powerful system can be built with [[Build Guide#Building with G34|G34]], but compatible cases and coolers can be hard to find.

Small (mITX to uATX), low power (25 to 40 W) open source machines can be built using the [[Build Guide#Building with AM1|AM1]], [[Build Guide#Building with AM3+|AM3+]], and [[Build Guide#Building with C32|C32]] platforms.

Many of the supported platforms can use ECC memory and have a working IOMMU. ECC memory support is important for machines running nonstop over long periods of time. The IOMMU enables PCIe device isolation or passthrough to a virtual machine.

{|class="wikitable" style="text-align:center;"
|+
! rowspan="2" |Socket Type
! colspan="4" |Motherboard
! colspan="4" |Per Socket
! rowspan="2" |ECC Support
! rowspan="2" |IOMMU Support
|-
!Size
!CPU Sockets
!Model
!Type
!CPU Cores
!Max Frequency (GHz)
!CPU TDP (W)
!Max RAM
|-
|[[Build Guide#Building with AM1|Socket AM1]]
|mITX
|1
|[[ASRock AM1H-ITX]]
|Desktop
|2 to 4
|2.20
|25
|16 GB
|Yes
|No
|-
| rowspan="3" |[[Build Guide#Building with AM3+|Socket AM3+]]
|uATX
| rowspan="3" |1
|[[Supermicro H8SML]]
|Server
| rowspan="3" |4 to 8
|3.80
|25 to 65
| rowspan="3" |64 GB
| rowspan="3" |Yes
| rowspan="3" |Yes
|-
| rowspan="2" |ATX
|[[ASUS Crosshair V Formula-Z]]
| rowspan="2" |Desktop
| rowspan="2" |5.00
| rowspan="2" |25 to 220
|-
|[[ASUS Sabertooth 990FX R2.0]]
|-
| rowspan="2" |[[Build Guide#Building with C32|Socket C32]]
|uATX
|1
|[[Supermicro H8SCM]]
| rowspan="2" |Server
| rowspan="2" |4 to 8
| rowspan="2" |3.80
| rowspan="2" |35 to 95
| rowspan="2" |256 GB
| rowspan="2" |Yes
| rowspan="2" |Yes
|-
|SSI CEB
|2
|[[ASUS KCMA-D8]]
|-
| rowspan="3" |[[Build Guide#Building with G34|Socket G34]]
|ATX
|1
|[[Supermicro H8SGL]]
| rowspan="3" |Server
| rowspan="3" |4 to 16
| rowspan="3" |3.80
| rowspan="3" |85 to 140
| rowspan="3" |256 GB
| rowspan="3" |Yes
| rowspan="3" |Yes
|-
|SSI EEB
|2
|[[ASUS KGPE-D16]]
|-
|SWTX
|4
|[[Supermicro H8QG6]]
|}

All of these platforms besides the AM1 support ECC memory, IOMMU, SR-IOV, SLAT, PCI-e ACS and are based on [[Orochi]] - AMD's high-power, high-performance platform for [[Family 15h]] systems.

If you're looking to build a lower-power quad-core system (such as for an efficient router or media player machine), you may be interested in a [[Trinity|Trinity/Richland]] or [[Kabini]] APU instead. For these, choose an [[FM2]] board for midrange desktop systems, or [[AM1]] for low-power systems with lightweight applications although please note that the AM1 currently lacks a functional IOMMU.

The 35W C32 4310EE and the 25W 3320EE are capable of 1Gbps routing and wireguard VPN on opnsense a FreeBSD distribution.

=== Building with AM3+ ===
{|class="wikitable" style="text-align:center;"
|+The Best AM3+ Processors by TDP
! rowspan="2" |Processor
! rowspan="2" |Cores
! colspan="3" |Frequency (GHz)
! rowspan="2" |TDP (W)
|-
!Base
!Full Load Turbo
!Half Load Turbo
|-
|Opteron 3320 EE
|4
|1.90
|2.10
|2.50
|25
|-
|Opteron 3350 HE
|4
|2.80
|3.10
|3.80
|45
|-
|Opteron 3380
|8
|2.60
|2.90
|3.60
|65
|-
|FX-4320
|4
|4.00
|4.10
|4.20
|95
|-
|FX-6330
|6
|3.60
|3.90
|4.20
|95
|-
|FX-8310
|8
|3.40
|3.70
|4.30
|95
|-
|FX-4350
|4
|4.20
|?
|4.30
|125
|-
|FX-8370
|8
|4.00
|4.10
|4.30
|125
|-
|FX-9590
|8
|4.70
|5.00
|5.00
|220
|}
''For all CPU models, see [[Socket AM3+#Orochi Processors]]''

coreboot-15h supports [[Socket AM3+]] on the ASUS [[Sabertooth 990FX R2.0]] and [[Crosshair V Formula-Z]]. The fastest AM3+ is the 8-core FX-9590. This platform uses DDR3 UDIMM (ordinary desktop RAM) in the usual dual-channel, 2-DIMM-per-channel configuration, and also optionally supports (UDIMM) ECC memory - DIMMs up to 16GB each are supported, for up to 64GB total.

As a consumer gaming platform, CPU coolers for AM3+ are common and still widely-available.

Unlike modern desktop CPUs (and other CPUs of its time), AM3+ is PGA socket, with pins on the CPU and holes in the socket. Be careful to avoid bending pins on the CPU during installation and removal. The socket on the motherboard is typically harder to damage.

AM3+ is currently the best option if you desire a comparatively fast libre firmware system for playing your proprietary games or 3D applications.

<gallery>
File:CROSSHAIR ORION 261019.png|[[orion]]
File:Komos_sabertooth.png|[[komos]]
</gallery>

=== Building with C32 ===
{|class="wikitable" style="text-align:center;"
|+The Best C32 Processors by TDP
! rowspan="2" |Processor
! rowspan="2" |Cores
! colspan="3" |Frequency (GHz)
! rowspan="2" |TDP (W)
|-
!Base
!Full Load Turbo
!Half Load Turbo
|-
|Opteron 4310 EE
|4
|2.00
|
|3.00
|35
|-
|Opteron 4256 EE
|8
|1.60
|1.90
|2.80
|35
|-
|Opteron 42DX EE
|4
|2.20
|
|3.30
|40
|-
|Opteron 4365 EE
|8
|2.00
|2.30
|2.80
|40
|-
|Opteron 4332 HE
|6
|3.00
|3.30
|3.70
|65
|-
|Opteron 4376 HE
|8
|2.60
|2.90
|3.60
|65
|-
|Opteron 4340
|6
|3.50
|3.70
|3.80
|95
|-
|Opteron 4386
|8
|3.10
|3.40
|3.80
|95
|}
''For all CPU models, see [[Socket C32#Orochi Processors]]''

[[Socket C32]] motherboards covering both 1 and 2 socket configurations are supported. The fastest C32 CPU is the 8-core Opteron 4386, and UDIMM, RDIMM, and LRDIMM memory are all supported. Each CPU supports 2 memory channels, and all coreboot-15h-supported boards are 2-DIMM-per-channel. Unlike with G34, C32 CPUs support 64GB LRDIMMs in ''all'' slots - this means that, despite having half as many slots, C32 motherboards surprisingly support the same 256 GB per socket as G34, albeit with fewer channels.

C32 CPUs use LGA sockets, like Intel or newer AMD CPUs. This generally makes the CPU less fragile, but the socket on the motherboard more so.

As with modern PC hardware, if you purchase a C32 motherboard without CPUs installed, inspect its sockets closely for bent, damaged, or dirty pins.

Socket F 3.5 pitch coolers can be used for C32 and can be far more affordable and still available new, see the [[Coolers]] page for more information.

Early revisions of certain motherboards only support the 41xx CPU and must be avoided.

Most of the 2U server coolers are insufficient for the 95W C32 CPU's to be under 55C at low and quiet fan speeds when in use so it is advisable to obtain a 3U/4U case if you want it close to your desk.

<gallery>
File:KCMA-D8 ponos.png|[[ponos (2025)]]
File:H8SCM talos.png|[[talos (2025)]]
File:H8SCM komos.png|[[komos (2025)]]
</gallery>

=== Building with G34 ===
[[File:Qubesotron_2026.jpeg|thumb|[[Qubesotron]] - a build using the [[G34]] [[KGPE-D16]]]]
{|class="wikitable" style="text-align:center;"
|+The Best G34 Processors by TDP
! rowspan="2" |Processor
! rowspan="2" |Cores
! colspan="3" |Frequency (GHz)
! rowspan="2" |TDP (W)
|-
!Base
!Full Load Turbo
!Half Load Turbo
|-
|Opteron 6366 HE
|16
|1.80
|2.30
|3.10
|85
|-
|Opteron 6338P
|12
|2.30
|2.50
|2.80
|99
|-
|Opteron 6370P
|16
|2.00
|2.20
|2.50
|99
|-
|Opteron 6328
|8
|3.20
|3.50
|3.80
|115
|-
|Opteron 6380
|16
|2.50
|2.80
|3.40
|115
|-
|Opteron 6386 SE
|16
|2.80
|3.20
|3.50
|140
|}
''For all CPU models, see [[Socket G34#Orochi Processors]]''

[[Socket G34]], usually on the [[ASUS KGPE-D16]], is probably the most popular and best-known platform for FOSS firmware on AMD systems. G34 motherboards were made with 1, 2, and 4 sockets, and coreboot-15h supports boards covering all of these configurations. The fastest G34 CPU is the 16-core Opteron 6386 SE, and UDIMM, RDIMM, and LRDIMM memory are all supported. Each CPU supports 4 memory channels, and all coreboot-15h-supported boards are 2-DIMM-per-channel. RDIMMs up to 32GB, or LRDIMMs up to 64GB each, are both supported. Despite this, two 32GB RDIMMs can be used per channel, versus only one 64GB LRDIMM - this means that the memory limit is 256 GB per socket, whether you use RDIMM or LRDIMM memory. RDIMM is generally the fastest, least-expensive and most-compatible option.

Good G34 CPU coolers can be difficult to find - many G34 servers used passive CPU coolers reliant on specific fan and baffle arrangements, which are not easily adapted for standard PC cases in custom-built systems. A list of relevant CPU coolers is available on the [[Coolers]] page - the rare Noctua G34 coolers are well-regarded and highly-prized, while Dynatron active server coolers are sometimes still available used. Depending on what you can find, it may be easier to [[Cooler_Adapter|adapt a modern CPU cooler to fit]] instead.

G34 CPUs use LGA sockets, like Intel or newer AMD CPUs. This generally makes the CPU less fragile, but the socket on the motherboard more so.

As with modern PC hardware, if you purchase a G34 motherboard without CPUs installed, inspect its sockets closely for bent, damaged, or dirty pins and the CPU for damage to the components or contacts on the bottom.

There are several pre-built KGPE-D16 systems commonly available with low wear such as the Barracuda Opteron G34 which may be a good choice as they already come with the hard to find heatsinks and 16 core CPU's.

=== Building with AM1 ===
The [[ASRock AM1H-ITX]] motherboard was recently added to the [[coreboot-15h]] project. It is still in a testing phase. The [[ASUS AM1I-A]] is maintained by an external project.

=== Building with FM2 ===
Two [[Socket FM2]] motherboards are supported by coreboot, but have not been thoroughly tested by the 15h community. These are the [[ASUS F2A85-M]] and [[ASUS A88XM-E]].

== PCI Express Devices ==
[[File:PM1725a.jpg|thumb|A Samsung PM1725a HHHL SSD - note the PCIe x8 card edge]]

The [[Family 15h]] and [[Family 16h]] platforms supported by coreboot-15h support up to PCI Express 2.0 ("Gen2") - a single Gen2 x16 slot delivers 8 GB/s of bandwidth. Compared to newer platforms, this can be a notable limitation for bandwidth-intensive devices such as GPUs or NVMe storage. For this reason, it's a good idea to select PCIe devices with more lanes whenever possible.

{| class="wikitable" style="text-align:left"
|+ PCI Express link performance
|- style="line-height:120%"
! scope="col" rowspan=2 | Version
! scope="col" rowspan=2 | Year introduced
! scope="col" rowspan=2 colspan=2 | Line code
! scope="col" rowspan=2 | Transfer rate<br>(per lane)
! scope="col" colspan=5 | Throughput (GB/s)
|-
! scope="col" | x1
! scope="col" | x2
! scope="col" | x4
! scope="col" | x8
! scope="col" | x16
|-
! scope="row" | 1.0
| 2003
| rowspan=5 | NRZ
| rowspan=2 | 8b/10b
| 2.5 GT/s
| {{shade|1.25|0.25|align=left}}
| {{shade|2.5|0.5|align=left}}
| {{shade|5|1|align=left}}
| {{shade|10|2|align=left}}
| {{shade|20|4|align=left}}
|-
! scope="row" | 2.0
| 2007
| 5.0 GT/s
| {{shade|2.5|0.5|align=left}}
| {{shade|5|1|align=left}}
| {{shade|10|2|align=left}}
| {{shade|20|4|align=left}}
| {{shade|40|8|align=left}}
|-
! scope="row" | 3.0
| 2010
| rowspan=3 | 128b/130b
| 8.0 GT/s
| {{shade|4.925|0.985|align=left}}
| {{shade|9.845|1.969|align=left}}
| {{shade|19.69|3.938|align=left}}
| {{shade|39.385|7.877|align=left}}
| {{shade|78.77|15.754|align=left}}
|-
! scope="row" | 4.0
| 2017
| 16.0 GT/s
| {{shade|9.485|1.969|align=left}}
| {{shade|19.69|3.938|align=left}}
| {{shade|39.385|7.877|align=left}}
| {{shade|78.77|15.754|align=left}}
| {{shade|157.54|31.508|align=left}}
|-
! scope="row" | 5.0
| 2019
| 32.0 GT/s
| {{shade|19.69|3.938|align=left}}
| {{shade|39.385|7.877|align=left}}
| {{shade|78.77|15.754|align=left}}
| {{shade|157.54|31.508|align=left}}
| {{shade|315.075|63.015|align=left}}
|}

This table shows the throughput of all PCIe lane widths, from Gen1 through Gen5. The advantages of additional PCIe lanes on a Gen2 chipset should be clear - a Gen2 x16 link provides comparable bandwidth to a Gen3 x8, or a Gen4 x4.

Extended PCI-e features such as Above 4G Decoding, Large/ReBAR, ARI and ATS are currently not supported by 15h coreboot but could potentially be added in the future as the chipset should support them.

PCI-e ACS is fully supported with the excellent IOMMU groups required by Qubes/Xen and VFIO device assignment.

SR-IOV is supported and should work fine under the limitations of not having ARI reducing the max VF's per bus.

=== Networking Cards ===
Almost any modern networking device should be compatible if it doesn't require large BAR support:

Most 15h workstation/server boards come with dual onboard Intel 82574L interfaces, since they do not feature an on-board flash chip they are safer for direct device assignment performed without the use of SR-IOV. Not assigning the ROM BAR to the guest may improve security for direct-attach.

It's recommended to use SR-IOV for safe device assignment and to lock the flash descriptors with intel ethernet tools if you're using a PCI-e network interface card in order to ensure maximum security.

'''1Gbps:'''

'''Intel i350:'''

This bridgeless and switchless PCI-e device with SR-IOV is available used and new in a variety of different configurations if you desire additional 1Gbps ports.

It is advised to use an intel firmware tool to ensure that iPXE/iSCSI is disabled on the re-writable ROM.

'''Broadcom BCM5719:'''

Considered a more free device than the i350 as substantially more logic is performed by the host loaded firmware instead of the card ROM. FOSS firmware has been developed for the RaptorCS Talos 2 LOM's which should also work in independent 5719 PCI-e cards for iPXE or BMC communication.

Removing the firmware from the card and locking the flash is considered best for security as the Linux drivers should provide general functionality without it and would likely make this the most secure option.

https://github.com/meklort/bcm5719-fw

https://github.com/meklort/bcm5719-fw/issues/232 (includes a list of card part numbers)

'''Intel 82576:'''

The quad port '''82576''' supports SR-IOV but it is a switched design and thus requires larger amounts of resources, their use could result in your graphics devices not receiving the proper BAR's. Security and flexibility is also reduced as each pair of ports shares an IOMMU group.

'''10Gbps:'''

(10/40 Cards without large BAR requirements, binary blobs or re-writable on-board firmware required for basic functionality should be listed here.)

TBD

'''25/40Gbps:'''

TBD

=== GPUs ===
Most high-end PCIe GPUs (old and new) support using all 16 lanes, but certain newer midrange cards are x8 or x4 and could potentially limit your 3D performance when limited to PCI-e 2.0

Newer cards will likely be highly CPU limited on the fastest available 15h CPU's.

'''''Recommended cards:'''''

AMD Polaris as the last generation of graphics cards without the vPSP, such as the Radeon RX590 8GB, the single slot Radeon Pro WX 7100 8GB or the low profile WX 4100.

Although the vPSP is restricted by the IOMMU and has nowhere near the level of access of it's mainboard counterparts it does prevent the theoretical development of owner controlled firmware for a video card which is already considered a very complex undertaking and will likely never happen.

If you do not care about that or consider the claim of the vPSP theoretically preventing hostile internal firmware re-writes as a benefit then potentially a newer x16 card could be purchased.

=== NVMe SSDs ===
[[File:M.2 Adapter.webp|thumb|A common generic M.2 adapter card kit. The bottom slot is for PCIe M.2 drives, the top slot (and cable) are for SATA M.2 drives.]]

Few motherboards supported by coreboot-15h have built-in M.2 slots. However, a PCIe M.2 SSD can be used in a PCIe slot using a common NVMe-to-x4 adapter card (many also allow an additional M.2 SATA SSD to be connected to a SATA port). A Gen2 x4 slot provides 2 GB/s of PCIe bandwidth - if your SSD's sequential read and write speeds are below 2000 MB/s, PCIe 2.0 will not bottleneck it. However, many NVMe SSDs are capable of more.

The D16 systems support PCI-e Bifurcation via the staging branch with two x16 slots capable of x8/x8 and configured in menuconfig thus making a four slot NVMe Cassette able to use two cards in position one and three.

It has yet to be added to the D8 but it should also work on this platform or any other with an electrical x16 slot.

Higher NVMe bandwidth on these platforms requires a directly attached SSD with more than 4 PCIe lanes - since the M.2 connector is only x4, this means using an AIC (Add-In Card)-format SSD, which installs directly in a PCIe slot. The following AIC SSDs are known to be capable of more than 2000 MB/s sequential throughput over at least 8 PCIe lanes:

{| class="wikitable sortable"
|+ Add-In Card SSD examples:
|-
! Model !! Capacity !! PCIe Width !! Sequential Read (MB/s) !! Sequential Write (MB/s) !! Random Read IOPS !! Random Write IOPS
|-
| Samsung PM1725a HHHL || 1.6/3.2/6.4 TB || x8 (up to Gen3) || 6200 (~3600 on Gen2) || 2600 || 1,000,000 || 180,000
|-
| Samsung PM1735a HHHL || 1.6/3.2/6.4/12.8 TB || x8 (up to Gen4) || 7000 (~3600 on Gen2) || 3200 || 800,000 || 135,000
|}
Another choice is a four slot switched NVMe PCI-e x16 card as this would enable the full usage of multiple modern PCI-e x4 SSD's with an oversubscribed PCI-e 2.0 x16 uplink if the switch supports lane rate conversion on the uplink. If you wish to assign NVMe devices to virtual machines one at a time the switch must also support ACS.

NVMe cassettes both switched and bifurcated can also be used to add other types of PCI-e M2 devices to a system with limited expansion slots.

== System Cooling ==
'''In order to ensure a long component life it is very important to ensure that your motherboard temperatures remain at optimal levels.'''

The primary heat sources on a motherboard that need cooling are the CPU, RAM, VRMs, Northbridge, Southbridge, and GPU. Internal sensors are used within the CPU to adjust fan speeds to maintain safe CPU temperatures. Many processors can be configured to throttle if the CPU die is becoming unsafely hot as a secondary protection mechanism. Dedicated GPU cards often operate the same way. The remaining components (RAM, VRMs, Northbridge, and Southbridge) all expect to be sufficiently cooled by case airflow. This is where differences between "Desktop" and "Server" motherboards become important.

[[File:Desktop vs Server.png|border|600px|A visual comparison of Desktop (left) and Server (right) motherboard cooling expectations.]]
[[File:Server air shroud.png|border|375px|A server air shroud condenses and focuses airflow over key components.]]

Server boards are designed for small cases with loud, powerful fans. Air shrouds are frequently utilized to further condense air over key components. Desktop boards often have larger heatsinks on the VRMs, Northbridge, and Southbridge to allow for quieter, less powerful fans in an office environment. A pair of motherboards with similar components is shown above to highlight the differences between Desktop and Server designs. The Server motherboard has significantly less cooling on the VRMs and no heatsink at all on the Southbridge.

Even larger Server boards, such as the [[KGPE-D16]], can be found with '''no VRM cooling''' despite housing more powerful processors than the two boards shown above.

Desktop systems largely place the motherboard perpendicular to the ground, allowing hot air to naturally flow towards the "top" of the motherboard. Heatsink fins and RAM are oriented to utilize this passive heat convection. Servers largely orient the motherboard parallel to the ground and expect "front to back" airflow in the case. Installing a Server motherboard in a vertical Desktop case can cause cooling problems for the installed RAM; the RAM modules will be stacked above each other, forcing the "topmost" module to absorb a tremendous amount of heat from the modules beneath it. The "topmost" module in a fully populated, vertically oriented Server motherboard can rapidly exceed 120°C under load without sufficient cooling.

[[File:Supermicro Workstation.png|border|375px]]

Workstation systems utilize Server motherboards in a vertical case, similar to Desktops. Powerful fans are placed along the edge of the motherboard, housed in green in the above example, to provide concentrated "front to back" airflow over the motherboard. If you are building a Workstation, it is best to choose a tight fitting case with high pressure fans positioned close to the motherboard.

== Shopping Tips ==

It is recommended to purchase later revision boards without visible dust buildup as they will likely be in better condition.

== Configuration and Tuning ==
'''Power Conservation:'''

Compile all PCI-e power saving options and force enable ASPM for all devices in your operating system in order to reduce CPU wakeup.

Use nohz=on and nohz full kernel command line options for a tickless system.

CPU Governor ondemand or conservative.

Disabling WoL with ethtool on each interface will shut off the network interfaces when the system is off and save a few watts of power, WoL is why the LOM status lights are on when the system is plugged in.

Using the jumpers to disable unneeded on board devices such as VGA or the LOM's since the 82574L has ASPM disabled in the e1000e driver and the VGA doesn't work at all without a blob on the Supermicro motherboards.

'''Security:'''

Microcode updates are highly recommended in order to provide secure operation of the Piledriver IOMMU, fix CPU timing errors and provide Spectre related enhancements.