Family 15h

Family 15h (also known as fam15h, or ambiguously as fam15) is a family of AMD microprocessors corresponding to the Bulldozer, Piledriver, Steamroller, and Excavator microarchitectures.

Like other AMD family names, 15h ("15 hexadecimal") is a mostly-arbitrary, somewhat-sequential (new processor families receive unused higher family numbers) number, returned by the x86 CPUID instruction as a "Family number", and commonly written in hexadecimal. 15 in hexadecimal corresponds to the number 21 in decimal, meaning that while "Family 21" would also be a valid, if confusing, name for these CPUs, "Family 15" might in fact refer to fam0Fh (K8 CPUs, first released in 2003).