Скачать или смотреть stuttering pc in games and browser

When I open rocket league I randomly get unplayable fps. When I hop into a match it's unplayable until I switch between tabs multiple times (like shown in the video). I don't know why this happens. The problem occurs while using the pc normally too (like while switching a tab while watching a video, sound and screen stutters for a second sometimes)
The problem started after me using a new motherboard on my system.
Things I did that didn't solve the problem:
-Resetting windows, switching between win 10/11
-Deleting my Display Drivers with DDU and downloading them freshly also trying out different driver versions.
-Closing unnecessary apps and applying other general fps boosting methods.

This isn't normal since my pc is able to run this game 180+ fps easily sometmimes (used to be always before motherboard switch)

What might be the cause? I need help