PC causes loud PSUs

[Darkwasp]

My brother's PC has been causing PSUs to spin their fan loudly at 100%. Any PSU, including my Cooler Master Silent Pro M 600 (40A on the +12v rail) will spin to the maximum when plugged in to the motherboard.

We determined that this was likely caused by the motherboard which he had previously shorted by forgetting to put in the spacers. However, we ordered a new one of the exact same model and when he put it in (without shorting it) the same thing happened. Almost.

Now instead of a constant 100% spin, it starts at 100% for about 3 secs then pauses then resumes 100% indefinitely.

His PSU works in my PC silently, and as I said my PSU spins up to 100% in his. And even if the motherboard and CPU are the only things plugged into the PSU, it still spins 100%.

Which leaves only 3 possibilities. (I think)

The new mobo is defective
The CPU fan has a sick sense of humor (and evil spirits)
or
The CPU has a weird voltage issue

Motherboard: http://www.newegg.com/Product/Produc...82E16813138179

CPU: http://www.newegg.com/Product/Produc...82E16819103817

His PC shouldn't be maxing these power supplies out:

His PC:
1 DVD drive
2 HDDS
1 ATI HD 4830
1 Phenom II X2 545 80W

My PC:
1 DVD Drive
2 HDDs
1 ATI HD 6870
1 Intel i5 750

And both PSUs are quiet on mine.

 

[mdd1963]

I'd be checking assorted temp monitoring/PC health/fan settings in the BIOS very carefully....

 

[Darkwasp]

Not having any luck in BIOS.

I should note that after the initial boot, the fan speed is constant no matter what. No short pauses for restarts.

The only way to quiet it down is to unplug the CPU power or CPU fan. Of course this just means that it isn't even POSTing.

EDIT:

Here's an interesting development for you.

CPU Smart Fan. We just enabled it. For some reason its effecting the PSU fan. It's running quiet now, but it has it's ups and downs like you would expect from Smart Fan.

Why is this happening? The way I see it this is a work-around fix.