SSE2 is the second
SIMD instruction set designed by
Intel. SSE2 was added to the
IA32 instruction set with the release of the
Pentium 4 CPU in 2001.
SSE2 adds support for 64
bit double precision floating point and for 64, 32, 16 and 8 bit integer operations using the eight original 128 bit XMM
registers. SSE2's integer instructions largely replace the need to use the older
MMX instruction set. But SSE2 does not completely replicate MMX's total functionality.