WEBThe 64-bit extension created by Advanced Micro Devices (AMD) to Intel's x86 architecture (later licensed by Intel); commonly termed x86-64, AMD64, or x64: AMD's AMD64 extensions (used in Athlon 64 , Opteron , Sempron , Turion 64 , Phenom , Athlon II , Phenom II , APU , FX , Ryzen , and Epyc processors)