Electronic hiss noise on newly build pc

I have a problem with a new computer. Customer complains about a hiss noise. I know the sound, you’ve probably all heard it before. If you have headphones, plug them in the on-board audio port and turn up the volume and render some 3d graphics.
The problem is, the noise is not comming from the headphones, but from the computer it self. I’ve tested PSU, GFX + turned off fans. Thats not it.
I am running out of ideas. Can anyone help? I have never heard this noise comming from the actualy computer before. Well once, but it was the GFX card that was the problem there.

The noise is usually there after windows boots. However it’s also there when you reboot the system after it has been turned on for a while.

The system specs:
Asus M2N32-SLI/Deluxe, nForce590 SLI AM2
AMD X2 4200+ AM2
Corsair TWIN2X2048-6400C4, 2x1024MB
XFX GeForce 7600GT, 256MB, PCI-E
Chill Innovation CP-520A3, 520W, ATX2.2
WD Caviar SE 1600JS, 160GB, SATAII, 8 MB

Thanks in advance.

I have heard this hiss noise on a couple new ASUS motherboards, but anyway they all are functioning very well, as far as I know.

Damnit, if it’s the motherboard I’ll have to take the whole thing apart. Oh well, another day in the life of a computer geek, eh? !

Thanks for your reply, Oleh.

The energy storage components (coils and capacitors) can make some small but audible high frequency noise under some conditions.

How bad is it? You could try just using some louder fans so that the customer cant hear it anymore. :stuck_out_tongue:

There is 4 fans running and the sound is actually louder than them! Even when the stock amd fan is running at full load the noise is louder.