[NEEDS INFO] Very choppy for some reason - please help

I have a high end gaming PC, I played Xonotic on max settings in the past with like 200+ FPS. And then randomly one day I start up Xonotic and it is extrememly choppy, almost unplayable. Says constant 160+ FPS on the bottom right, but it is crazy choppy. I have no idea what happened.

Xonotic is the only game this has occurred on. I run other high end games flawlessly. So I know there's something wrong with this specific game.

Already tried re-installing btw.

EDIT: This seems to only happen when I load Xonotic through Steam with the game overlay. O_o

Have you tried starting the game with the other executable? (there are 2, or even 4 for windows that you can use - xonotic.exe, xonotic-sdl.exe and 2 64bit ones)

If this only happens through Steam, what are the differences between running in Steam and running outside of Steam? Is it the same executable being run? Why do you need to run via Steam?