Bad PSU?

[Simonas95]

Hello all,
I have strange problem. After using my 4 years old PC for 3-4 hours, I start hearing this sound (I`m guessing it`s coming from PSU):
http://www44.zippyshare.com/v/24785770/file.html (Open it with iTunes)
Usually, I get it when my CPU or GPU is a bit loaded (gaming/converting videos), but sometimes (after more then 5 hours of usage) it goes on while I`m just scrolling Youtube page. I don`t hear this sound when I just power on PC. It becomes louder and more frequent by using computer. Oh, and it starts even faster, since I overclocked my E6750 from 2.66GHz to 3.2GHz (stock cooler, no vcore adjustments were made, also I have slow 667MHz RAM, maybe it`s too much oc for it?). Also, I`m running my 8600 GT OC`ed about 15%. Temps are quite normal: CPU doesn`t go higher than 62C, GPU - 72C. But my biggest problem is that after this sound, gaming (WoW/MineCraft) freezes (system becomes unresponsive for about 30sec-2min) my PC, and after 3-4 freezes it restarts by itself.
My PSU is made by Inter-Tech (I got it with case)
420W
38A (on 2 12V rails)
Anybody had similar problem? Any help would be greatly appreciated

 

[scout_03]

fan sound running at max from psu to cool down

 

[Simonas95]

Actually, i don`t think that PSU is overheating. It only becomes noisy while playing games or converting videos. If I stop doing it - PSU almost immediately becomes less noisy. Any other thoughts?

 

[scout_03]

another thing your temp at 72c for graphic is a bit high the max i have is 56 c