>>285616903
If a game can't maintain 144fps, it'll drop to 72fps and steam's software will synthesize every other frame, which causes some visual artifacts but is still very smooth, not jittery. If you can't maintain 72fps (vrchat), it'll drop to 48fps and synthesize 2/3 frames, or 36fps, etc.

You can also change the refresh rate of the screen down to 90 or even 80, but I prefer the synthesized frames personally.