I recently purchased a new computer and have had a problem with the sound from day 1. When playing a game (protoype, farcry 2, etc..) there is a persistent static noise or high pitch whine, which i think is related to how much graphic rendering is taking place.
I've tried moving the sound and video cards to different slots and also moved some power cables around, but nothing has made a difference.
I believe this is an earthing issue because i can hear the noise in every audio plug i try (even with onboard disabled in bios). Interesting enough, i can also hear it if i plug the sound into my mp3 player and have the usb plugged into it at the same time.
Not software related as the same behaviour occurs on linux and windows 7.
Asus P6T motherboard
core i7 920
asus xonar dx
corsair hx620 psu
More about :persistent static noise earthing issue