Weird movement issue on the 3.3.5a client.

The problem is when i use the keyboard to move, my character randomly stops and moves very slowly while jittering at the same time. It looks so off, and it happens as well when i strafe or try to move in a circle. I usually move with the keyboard while holding my right mouse button so i can get the most accurate movement but this weird bug is making it insanely frustrating. What's going on? I've tried downloading many different torrents of the 3.3.5a client but all of them have the same issue. My framerate is normal as well so it's probably not up to that. What do?