Instead of trying to explain the sound, I recorded a quick sample which you can donwload here: noise.mp3
(the changes in frequency are when the mouse is being moved. I also amplified it a bit to make it easier to hear.)
Because my video card is very close the onboard sound, I assumed it was this (still might be?). Today I put in a new souncard 4 slots away from the video card and I still get the noise. It doesnt matter what the volume is on the pc or whether it's speakers or headphones, the noise is always there. Very irritating!
PSU: EarthWatts 500 Watt power supply
CPU: Intel E6750
RAM: 2x1gb corsair
GPU: Inno3d 8800 GTS 312mb
Motherboard: gigabyte GA-P35-DS3
I have a nice stereo setup, and this constant high pitched whine is ruining it!
The only solution I can think of is to use an external soundcard, but I would prefer to try and at least work out what's causing it, and knowing my luck it would probably still be there anyway!
Any advice or suggestions most welcome. Thanks.