P55M-UD2, question about the SYS_FAN header

Spicedaddy

Platinum Member
Apr 18, 2002
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Is there a way to disable the voltage control for the SYS_FAN header? I have my rear case fan hooked up to it (regular 3-pin fan), and it's running at ~500rpm instead of the rated 800rpm.

I looked in the BIOS and all the options are for the CPU_FAN header, nothing for the SYS_FAN.
 

lopri

Elite Member
Jul 27, 2002
13,314
690
126
Does the RPM of fan change? If there is no control in the BIOS, chances are the header supplies a fixed voltage. And often times on-board headers do not provide enough voltages for a 12V fan to run at full swing. If you connect a fan rated 1500RPM to a motherboard supplied header you'll get ~1200RPM max, etc.
 

Spicedaddy

Platinum Member
Apr 18, 2002
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Yes, the RPM changes according to System Temp... It's a 800rpm Slipstream, starts at 450rpm and I've seen it go up to 600rpm. I'm pretty sure it's voltage is being controlled according to temp.

Oh well, I'll just get the 1200rpm version, because 450rpm is pretty weak. :D

Other than this minor annoyance, this board is excellent for the price.
 

Fatbird

Member
Sep 15, 2009
27
0
0
It can not disable by BIOS, maybe getting a molex converter could solve your situation.
Convert the header directly from the big 4-pin ATX connector.
 

Spicedaddy

Platinum Member
Apr 18, 2002
2,305
77
91
Yeah, I just went through my box of cooling stuff and found an adapter... Problem solved!

Thanks for the replies guys!

<--happy new i5-750 owner :D