I was wondering generally, is SIMD a good idea for general purpose CPUs. Imagine if the current high end CPUs had double the number of cores, no SIMD, but possibly higher frequency and the algorithms that benefit from SIMD were all run on integrated accelerators instead.

At least as a side observer it looks like a huge number of very large registers take large portions of a core, for sure consuming a lot of power as well, just to sit idle while the core is running JavaScript. Can somebody with CPU architecture experience say what is the real tradeoff here.