Windows updated itself with absolutely no warning and now Dolphin is running at 10FPS.
For about 2 weeks when the exact same thing happened again. I took it to an IT repair place who fixed it (btw completely unfair that I had to pay to reverse a buggy update that I didn't even want) and everything was fine. I messed with windows settings and drivers and the situation kept getting I only use this machine for playing Dolphin (Gamecube emulator), it worked fine a month ago, but then an update was forced on me and the emulator started running at 10FPS (60 is normal).