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Power Supply Fan Running at Max Speed

Last response: in Components
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August 10, 2011 7:05:01 PM

So I have a problem with power supplies and their fans running at their highest possible R.P.M. for no apparent reason. I have tried different power supplies with higher and lower wattage, all behave the same upon boot up. Each power supply works fine in other computers as well as when jump started.

Please note, this is should not be heat related or dust related because I've tried new power supplies and they aren't running hot.

Any suggestions?
a b ) Power supply
August 10, 2011 8:15:42 PM

Is the PSU fan controlled by the motherboard? Are you 100% sure it's the PSU fan that runs at full speed?
August 10, 2011 8:46:38 PM

The PSU fan shouldn't be controlled by the motherboard but it appears it is. Yes I'm sure it the PSU fan because I unplugged all the other fans to check.
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a c 248 ) Power supply
August 10, 2011 8:56:49 PM

This is one of those weird issues caused by the motherboard, this isnt the first time i have seen this reported, and its very obscure as 99.999% of the time the fan is absolutely independent of the system and is controlled by a sensor in the PSU itself, but some motherboards have a special gift of being able to screw with units like that. What motherboard is it and which power supplies have you tested? Ill try to dig up one of the threads i had seen this in previously.
August 10, 2011 9:06:28 PM

The mother board is a GA-MA785GM-US2H (Rev. 3.3). I've tried several OEM power supplies I have lying around to test it, but the one I had used was a IN-WIN Power Man IP-S350CQ2-0 350W that came with the case and according to IN-WIN it has "Smart Thermal Control to Balance Noise & Cooling."

http://www.in-win.com.tw/US/products_power_series.php?c...
a b ) Power supply
August 10, 2011 9:10:51 PM

What happens if you don't connect the PSU fan cable to the motherboard? Is the BIOS configured to control the PSU fan speed?
August 10, 2011 9:13:11 PM

The PSU does not have a fan cable to connect to the motherboard, and I could not find a BIOS setting related to PSU fan. I've tried to see if the power saving settings is causing this but it doesn't seem to change it.
a b ) Power supply
August 10, 2011 9:22:16 PM

That's really weird. Is the outlet properly grounded?
August 10, 2011 9:41:50 PM

Yes, I've tried unplugging it from the surge protector and straight into a wall outlet, I've tried two different outlets both result in the same thing.
a b ) Power supply
August 10, 2011 10:14:21 PM

It's a good test as long as both outlets are on a different circuit.
August 11, 2011 12:46:54 AM

Is your PSU dirty?
August 11, 2011 1:06:09 AM

No, it's new.
August 28, 2011 6:57:55 AM

Hi, I have the same problem like you. I bought a xigmatek psu 700w and it runs at maximum speed all the time.the pc temp is low and the air that comes frome the back of the psu is cold. I really don't know why or what to do.the fan is 140mm and it should run at 600 rpm but is running at 1900 rpm.its quite bothering.
August 28, 2011 11:24:30 PM

What motherboard do you have?
July 22, 2013 1:09:39 AM

Hi, same problem here. I have the OCZ-ZT 750W. My mobo is a Gigabyte 990XFXA-UD3. But the PSU fan is load-controlled. Found that out on the specs on the box. I'm about to send it back because I can't take this sound anymore.
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