I just installed a 1GB GTX 280 and a Corsair 550W power supply into my PC. I have a Dell Dimension 9200 Quad Core 2.66 Ghz running Vista 32 bit and 4 gigs of Ram.
It seems that when the graphics card starts running anything beyond normal use the my audio starts slowing down, sort of sounds like reverb. My sound card is a basic SB Audgiy. It almost seems like the Graphics and Audio cards are conflicting.