My CPU has no e-Cores, but maybe this is of help to you:
At 4K with an undervolted RTX 3080, my i7-11700K @ 65 W provides the exact same framerates compared to 95 or 125 W.
I use Windows 10 x64 and tested Cyberpunk 2077, Ghostrunner and some older games (Dying Light 1, Mafia 3, Shadow of War...