SIMD parallelism has been improving on the CPU too – although the number of lanes hasn’t increased that much since the MMX days (128 to 512 bits), the spectrum

SIMD parallelism has been improving on the CPU too – although the number of lanes hasn’t increased that much since the MMX days (128 to 512 bits), the spectrum of available vector instructions has grown a lot. And being able to do eight or sixteen operations at the price of one is certainly nothing to scoff at. Autovectorization is a really hard problem, though, and manual vectorization is still something of a dark art, especially due to the scarcity of good abstractions. Programming with cryptically named, architecture-specific intrinsics and doing manual feature detection is not fun.