Not a pro here but the first thing that came to mind for me right off the bat (reading first post) was AVX instructions, which many others did as well. Offhand it eludes me but it should be relatively straightforward to verify whether iCue is or is NOT causing one of your AVX negative offsets to kick in, especially if you have something like HWinfo64 or another util that you can watch individual core clock multipliers on.
You could probably even verify which core(s) iCue is running on and watch those clocks. You'll be able to tell when AVX negative offset is kicking in on those cores by the clocks/multipliers they come down to. I've seen that watching stresstests with Prime95, Realbench, etc. when testing my OC stability. Course, it also depends how you've set the BIOS to manage core clocks, using turbo boost max or not, etc.
The other suggestion someone gave, try changing your AVX offsets, is a good one -- (change them downwards to a "more negative" offset to be safest) and see if those clocks change downwards by the new amount or not. That will more or less prove whether what you are seeing with iCue is due to use of AVX instructions by iCue on those cores.
I'll be honest, the more of this kind of stuff I see, the more I am coming to the conclusion that I should only have iCue installed in a special "configuring my lighting" Windows boot/installation that I only ever boot into when I want to change the lighting scheme and keep iCue far, far away from my general/everyday Windows boot/install.