mmhm.. it’s very difficult to say that CPU throttling (what you call downclocking) is a deterministic frequency reduction based on some instructions usage .. in facts most of the time, - throttling happens anyway when the CPU uses a lot of power and becomes too hot.
take care compilers can use AVX instructions even if you ain’t using’em explicitly like for coping struct, inlining memcpy or vectorizing loops etc. however the SIMD speed up generally voids the frequency slow down, so even if you see lower numbers your computation performance should be higher.
eventually be sure your system is super stable and super well-cooled then try using only 1 or 2 cores and see if your CPU keeps stepping down into a well defined license mode (lookup L0, L1, L2 nominal frequencies for your CPU). Only with sustained dense heavy use (1 x cycle) of AVX instructions you go to L2, with light use you may go to L1. if your frequency drop is arbitrary (well.. sort of) then it’s not that, however it could still be not that even if your discrete stepping down uses known patterns.
this said .. I really don’t think you should be worried about anything your CPU is doing regard its core frequencies 🙂
