Game lags to unplayable degrees whenever fullscreened

Fullscreen or borderless fullscreen causes the game to lag. I played for a while without this issue, and no new updates or mods were added to my game. But now when I try to play in fullscreen, the game will run fine for 1-5 seconds, then be stuck at around 30fps. Turning the game windowed instantly fixes the issue
Was this page helpful?