Phenom ( /fɨˈnɒm/) is the 64-bit AMD desktop processor line based on the K10 microarchitecture, in what AMD calls family 10h (10 hex, i.e. 16 in normal decimal numbers) processors, sometimes incorrectly called "K10h". Triple-core versions (codenamed Toliman) belong to the Phenom 8000 series and quad cores (codenamed Agena) to the AMD Phenom X4 9000 series. The first processor in the family was released in 2007.

AMD considers the quad core Phenoms to be the first "true" quad core design, as these processors are a monolithic multi-core design (all cores on the same silicon die), unlike Intel's Core 2 Quad series which are a multi-chip module (MCM) design. The processors are on the Socket AM2+ platform.

Before Phenom's original release a flaw was discovered in the translation lookaside buffer (TLB) that could cause a system lock-up in rare circumstances; Phenom processors up to and including stepping "B2" and "BA" are affected by this bug. BIOS and software workarounds disable the TLB, and typically incur a performance penalty of at least 10%. This penalty was not accounted for in pre-release previews of Phenom, hence the performance of early Phenoms delivered to customers is expected to be less than the preview benchmarks. "B3" stepping Phenom processors were released March 27, 2008 without the TLB bug and with "xx50" model numbers.

Advanced Micro Devices, Inc. (NYSE: AMD) or AMD is an American multinational semiconductor company based in Sunnyvale, California, that develops computer processors and related technologies for commercial and consumer markets. Its main products include microprocessors, motherboard chipsets, embedded processors and graphics processors for servers, workstations and personal computers, and embedded systems applications.

AMD is the second-largest global supplier of microprocessors based on the x86 architecture and also one of the largest suppliers of graphics processing units. It also owns 8.6% of Spansion, a supplier of non-volatile flash memory.

AMD is the only significant rival to Intel in the central processor (CPU) market for (x86 based) personal computers. Together they held 99.1 percent (Intel 80.3%, AMD 18.8%) of the CPU's sold for quarter three of 2011.^{[dubious – discuss]} Since acquiring ATI in 2006, AMD and its competitor Nvidia have dominated the discrete graphics processor unit (GPU) market, together making up virtually 100% of the market.