The AMD Phenom family is a 64-bit microprocessor family from AMD, based on the K10 microarchitecture. It includes the Phenom II X6 hex-core series, Phenom X4 and Phenom II X4 quad-core series, Phenom X3 and Phenom II X3 tri-core series, and Phenom II X2 dual-core series. Other related processors based on the K10 microarchitecture include the Athlon X2 "Kuma" processors, Athlon II processors, and various Opteron, Sempron, and Turion series. The first Phenoms were released in November 2007. An improved second generation was released in December 2008, named Phenom II. Processors with an "e" following the model number (e.g., 245e) are low-power models, typically 45W for Athlons, 65W for Phenoms.