Low FPS/Sound quality if mic is not on

I just got a new graphics card, an nVIDIA GeForce 9500 for my computer, it runs Cod4 and all source games flawlessly Except for garrysmod. Whenever my microphone button is not being pressed I get really shitty framerates and my sound is really low quality. It’s slowed down and really crackly. No such probloms in Singleplayer. only on multiplayer.

I tested it in a few other games and it seems that this happens for every source1 (Non-orangebox, hl2ep1) engine game or mod. Exept gmod for whatever reason.