Unreal Tournament Three: jitterines?

I just got unreal tournament 3 installed, and I'm experiencing some problems untypical of my computer. I have an 8800GT OCed by BFG, a E4300 OCed to 2.4 gigahertz, and two gigs of ram running 1:1 with the FSB. The harddrive is a 7200 rpm unit connected by a IDE line.

I've ran the game with everything disabled on 800x600 and with everything enabled up to 1280x1024: I still get some slowness. The audio plays back jittery and sounds garbled, yet the video comes through mostly crystal clear and crisp sans when the audio gets REALLY bad and then I have some jitteriness in the video. USually when I play the game I have perfect smoothness, but right around when the audio kicks in I start getting jittery sound, then the video playback can get garbled.

On mainscreen, its perfectly smooth. On play, its alright. Only when playing either one of hte mission videos OR during gameplay when sound kicks on is there a problem.

Anyone know whats up>

I have a similar problem during mission loading, the sound just stops for a second or 2 before continuing. But the rest of the game is perfect, I can even run it at 1680x1050 with everything at max without any problems (Athlon X2 4800 (2.4GHz, 1MB L2 each core), 2gig DDR400, Geforce 8800 GTS 640, X-Fi).
And yes I do have the latest drivers and such.