Later edit: Issue was caused by my Gigabyte motherboard bios, newer versions have a bug that messes up XMP profiles making the memory work very poorly when enabled.
My finding below was just a coincidence as flashing a new version disables XMP by default, but when I re-enabled it the issue was still there, so I had to go back to an ancient version to make it work again.
TL;DR if you recently updated your BIOS try going back to the previous version
Sharing my experience here maybe it helps someone:
I was getting around 130 fps with DLSS and high settings on a 10700k on z490 Aorus ultra + 5070ti.
I then updated my mb bios from an ancient version to version F24b and started having the issues described in this thread: CPU usage spiked to 100% and fps dropped to 30-40. I tried messing with all the settings in BIOS, like XMP and CPU overclocking and etc to no result. In the end I downgraded to bios F23 (which is 2 years older) and all the issues went away.
This new bios version mentions:
Maybe there's some interaction between these CVEs and the anti-cheat or who knows what causing the slowdown
