PSU makes hiss sound when plugged

[yquo]

I assembled the following: Athlon64X2 3600+, MSI K9AGM, 512 Mb DDR2 667 Mhz Kingston Value, WD 250GB SataII 16mb, 2 opticals LiteOn, cheap Omega case & PSU.

The PSU is "rated" at 450W with dual 12V rails of 15A & 14A each or viceversa.

When it is plugged to the power outlet without powering up the computer it makes a hiss noise, like thin eeeeeeee noise, (I don't know exactly how to describe it) when powered on the hiss seems to fade away.

I'm sorry for my noob question but is this hiss sound, something wrong or may it be some sort of PFC ?

 

[Valtiel]

I would say it would be a PSU problem. Usually bundled case/PSUs are the bottom of the barrel.

 

[yquo]

These are the voltages:

Everest| PcAlert4(MSI)
CPU| 1.18 - 1.22| 1.18 - 1.22
+3.3| 3.30 - 3.31| 3.30 - 3.31
+5 | 5.54 - 5.56| 5.05 - 5.07
+12 |11.92 - 12.04| 12.36 - 12.46

But most of the time they are quite steady, so no matter the voltages are quite good it might fail ? (I'm sorry to ask again, just to be sure because RMA is quite expensive here.)