[martinpw]

I'm having trouble finding good references now, but I am sure I remember reading that is was simply slowing the clock.

In my case, yes, Skylake would still be a win over older hardware, but the question is whether to use AVX512 or not. The workload is a real time animation system with a bunch of nodes in a graph that get evaluated in sequence. Some nodes would benefit from AVX512, but others would not. So the question is, if we vectorize those nodes that would benefit and get a speedup there, will the other unvectorized nodes now run slower as a result of the lower clock speed, canceling out the benefit.

It sounds like your case is a much better fit for AVX512. Out of curiosity, have you tried running on Xeon Phi, which also supports AVX512?