Complex sentence: The first widely-deployed desktop SIMD was with Intel's MMX extensions to the x86 architecture in 1996, which sparked the introduction of the much more powerful AltiVec system in the Motorola PowePC's and IBM's POWER systems.
Split into simpler sentences: The first widely-deployed desktop SIMD was with Intel's MMX extensions to the x86 architecture in 1996. This sparked the introduction of the much more powerful AltiVec system in the Motorola PowePC's and IBM's POWER systems.