Hello all. I'm having an unusual problem with a power supply whine and I hope someone can point me in the right direction, but let me give some background first... I had a Dell XPS 720 for a little over a year. One day I had walked away from the computer and sat back down and grabbed the mouse to move the pointer. Believe it or not, an arc of static electricity hit my mouse and the computer died right there on the spot. When trying to turn the power on the fans would come on but I would get no POST and no error lights or beeps. To make a long story short, Dell would not even talking to me about the problem without charging me since it was out of warranty, much less replace the obvious culprit... the motherboard. Because of that, and the fact that I discovered the power supply had proprietary connections, I decided to salvage the components and build a new PC with a new motherboard and power supply. I got an Asus P5N-D motherboard and a Zalman 750 watt modular power supply. The new system is working fine except for a whine from the power supply when the computer is powered on. I would compared it to the sound that can sometimes be heard from a computer monitor that is turned off, but much louder. It's not the warning signal for a video card that has 6-pin power connector unplugged (not that loud or consistent)... I can boot into Windows and graphics, temps, cpu speed are all normal. I unplugged the power supply from everything and shorted the main motherboard connector and there was no longer any whine when the PSU was powered on. Through some trial and error I have determined that the whine only starts when the 4-pin 12v power connector is plugged in. I have read in some messages in other forums from people who are having this problem occur with any power supply they put in their system. Could it be the motherboard? I am at a loss here and don't really have any alternate components to test with.
meh, there are lots of bizare things that could be causing it. First of all you could return it, or do some reasearch and try and find out a solution, the fastest way would be to mod it and replace the fan but void your warranty http://www.hardwareforums.com/how-shut-your-psu-up-make-silent-sexy-25121/ .
I don't think it's your motherboard mate - probably just poorly laminated/clamped transformer plates in the PSU. Short of having it replaced there will be very little you can do about it.
Have you tried another power supply to see what happens? I agree with Ashton and try another fan in that power supply..