Motherboard question: fan connectors

By Atwooooood
Nov 5, 2008
  1. so i just got in my asus p5q pro motherboard yesterday and stuck it in the case and decided just to hook up the front panel usb/audio/power button cords and hook up the case fans since i dont have the rest of the components yet.

    i have 3 120mm case fans installed and in the manual where the diagram is, it shows 4 different places for fans. 1 is the 4 pin cpu fan, 2 of them are for the 3 pin chassis fans, and one is a 3 pin labeled power fan.

    the manual didnt really specify what i was looking for. can one of the 120 mm fans be plugged into the power fan slot? if not, what goes in there and how do i go about hooking up the 3rd 120mm case fan.

    sorry for the lame noob question.
    dont want to mess my board up though by doing something stupid.
  2. EXCellR8

    EXCellR8 The Conservative Posts: 1,835

    I have one of those "power" fan headers on my motherboard too. I think it's meant to be used with a chipset cooler or something, that can be adjusted via BIOS. I have a regular 120mm case fan hooked up to it and it works fine...
  3. CCT

    CCT TS Evangelist Posts: 2,653   +6

    IF your PSU has a 3 pin connector coming out of it that is what you connect to the 3 pin mobo 'power connector'.

    The psu would have 2 fans and 1 is controlled by load and gets its power from that connection.
  4. Atwooooood

    Atwooooood TS Enthusiast Topic Starter Posts: 63

    so CCT,

    the 3 pin connector on the PSU plugs into the 'power connector' spot on the mobo and the fans are hooked up through the psu?
  5. CCT

    CCT TS Evangelist Posts: 2,653   +6

    It goes like this: there is LITTLE info re the 'power fan' 3 pin connector anywhere - weird!

    Why 3 pins if it only measures fan speed? Why bother? They say 'so you can tell if the PSU fan fails". But, I have have 2 fans!

    Basically, I developed my own pet theory that the fan would give speed and be thermally controlled (I mean, why report the speed if it is going 2500 all the bloody time, right?).

    Of course, this is the use of logic in computer science, so HEY!
  6. Cinders

    Cinders TechSpot Chancellor Posts: 872   +12

    The "Power Fan" header probably will not actually power a fan. It is there to monitor the fan in your power supply if your PSU extends the fan probe (wire) outside its case.
  7. EXCellR8

    EXCellR8 The Conservative Posts: 1,835

    Hmm, well I have a regular 120mm case fan hooked up to the one on my board and it's working just fine. The header is labeled "PWR FAN" so maybe it's different. I do know that some PSUs have fans that can be monitored via 3-pin connector but I'm pretty sure the one on my board is for an optional chipset fan... Looks like we have two different possibilities for this header. They should really label them better imo...
  8. Atwooooood

    Atwooooood TS Enthusiast Topic Starter Posts: 63

    i agree
  9. Cinders

    Cinders TechSpot Chancellor Posts: 872   +12

    I've had many motherboards and have encountered PWR FAN headers that wouldn't power a fan and ones that would power a fan, so my use of the word "probably" was to strong. I should have used the word "may" instead. The motherboard listed in my system specs has a PWR FAN header that will not power a fan. At first I didn't realize that the header was just used for monitoring the PSU fan and actually destroyed a good 80mm fan before I discovered my mistake.
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