Question Mouse Movements causes stuttering/freezes in games after BIOS Update

Jul 6, 2019
Because of my RAM not running at its vendor specified timings and speed, I updated my BIOS this morning. The RAM now runs at its vendor specification, however since the update, games start to stutter and freeze while I move the mouse. If I play with a controller, everything is smooth as butter. The issue also gets worse with a higher mouse polling rate, meaning it's not as noticeable on a polling rate of 500hz (still noticeable enough to be really annoying) and gets absolutely terrible at 1000hz, which I used just fine all the time before updating my BIOS this morning. Pro4/index.asp#BIOS
This is the board, I updated to the newest version (4.20).

I tried turning the ram speed and timings back to what they were before I updated the BIOS, unfortunately that does not help. Downgrading the BIOS is apparently not possible either, at least that is what ASRock states right next to the BIOS version.

Any ideas? I'm kinda lost here, and would really appreciate some help.