anyway, here is my quick + dirty findings. make of them what you will (click to enlarge images). the thing i noticed is that my CPU never goes above 4.8GHz so that would indicate whatever process is causing the rise in usage/temps is an AVX instruction. i have a -2 AVX offset. CPU is meant to run at 5.0GHz unless there is an AVX load in which case it will downclock to 4.8GHz. look at CPU temperature/usage and it seems that the Epic Client is also using my GPU which shows increased usage/temps.
without anything running on my PC:
with Epic games client opened and running idle:
with Steam client opened and running idle: