Not sure if anyone else has had this issue as far as google can tell me, so this is my last resort. Basically my brother got a new PC, I installed TF2 on it and plugged in my mouse (Deathadder) because I prefer it over his Logitech mouse. Everything ran fine, no issues then. But I stopped playing on his comp after a couple of days when he was around. Mind you in this time he also played TF2 on his account. When I went back onto his comp, I noticed that my sensitivity in-game felt really awkward, as if it were really heavy or smooth, no matter how high my sens was.
I don't think it's an FPS issue as the game runs perfectly fine, but the mouse movement feels really uneasy and uncomfortable. I've tried different mice, and even tried playing on my brother's account, same issue. On his old PC I had the same issue with CSS. Now, my sens in CSS is fine, but TF2 is fucked.
Any ideas? :c
edit: I even meddled with mouse accel and such and there was no difference