I'm using Win Vista 64.

This was reproduced using both the Win32 and Win64 clients. This was also reproduced using the on-board Conexant High Definition Smart Audio 221 and a Soundblaster X-Fi Surround 5.1 card.

I can hear everyone on the server just fine. However, when I try to speak there is intense stuttering to the point that it sounds like someone trying to beatbox horribly.

Teamspeak 2 and Ventrilo sound just fine so I'm only getting this error on Teamspeak 3.