Possible PSU issue?

[Miller]

I got my new computer parts the other day, and everything has been running perfectly (after a few small holdups), but there's one nagging problem that I can't seem to get rid of.

Every once in a while, at what seems like entirely random points in time, my computer will begin to make a very high-pitched "buzzing" noise, and I can not for the life of me figure out where the heck it's coming from.

My primary suspect is the CPU, only because the sound seems the strongest there. What I find odd is that my system is not impacted in any way by this other than a slight annoyance for the minute or two that it lasts.

Another suspect is my video card, but I never had any problems with it in my old computer, so I highly doubt it's that.

I personally don't want to have to send back my PSU and wait for a refund and go out and buy a new one (which could take a couple weeks), as everything seems to be working fine (this has been an ongoing problem since I built it a week and a half ago); I just want to get it fixed.

My computer:
Intel Pentium 4 3.2ghz
ABIT AS8
1gb PC3200 DDR 400mhz
SoundBlaster Audigy 2
GeForce FX5700 Ultra (Replacing with a 6800GT on Tuesday or so)
Ultra 500 watt ATX Power Supply

Thanks in advance for any help.

PS. A point of interest may be that when the noise IS going, whenever that may be, certain things seem to make it better or worse. That is, if I run the Counterstrike Source video stress test, it gets loud and consistant, but if I connect to a server (where all there is is a black background, a grey window and a small white loading bar) it stops entirely. That's originally why I suspected my video card.

 

[Slacky]

At first I thought you might be hitting a thermal alert, but you said the sound changes during games. That makes me think that there is a wire rubbing against a fan motor. As the part heats up, the fan control speeds up the blades, that changes the pitch of the sound. Check All fans. Make sure the CPU fan is clear of wires, this is the most likely location. Some power supplies also have speed controls, get a flashlight and look inside if you can. Worst case, stick a pencil in it to stop the blade from turning to test if it is the source. Just as an FYI, if you do this to your CPU fan, the AS8 motherboard will turn off the PC, you have to uncheck the BIOS option to shutdown the PC during fan failure.

Slacky

 

[Stiler]

I second what he said above.

I had the same problem and it annoyed the hell out of me, then i opened my case and there was just a tip of a cord that the fan kept hitting that was causing it.