Instruction set

RISC (reduced instruction set computer)
CISC (complex instruction set computer)
EPIC (explicitly parallel instruction set computer)

MMX (Multi Media eXtension / Matrix Math eXtension)
MMX2
SIMD - Single Instruction, Multiple Data
ISSE / SSE(Internet Streaming SIMD Extension [former KNI - Katmai New Instructions])
ISSE2 / SSE2 (Willamette New Instructions [SIMD double precision])
SSE3 (Prescott New Instructions)
Jackson Technology (Multi-Threading for P4)
Yamhill Technology (x86-64 for P4 licensed from AMD)
3DNow!
3DNow! Enhanced (3DNow! plus 19 MMX commands plus 5 DSP/communications commands)
3DNow! Professional (3DNow! Enhanced plus 52 ISSE commands for full ISSE support)
AltiVec
SPARC VIS
HP-PA MAX1 / MAX2 (Multimedia Acceleration eXtension)
MDMX (MIPS Digital Multimedia Extensions)