CPU Fan speed, running too fast

Discussion in 'Computer Games and General Discussion' started by Zetta_x, Aug 6, 2012.

  1. Zetta_x
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    Zetta_x The Insane Statistician

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    About a year or 2 ago, I had an HP desktop with a propitiatory foxconn motherboard. I ended up replacing it with an ASUS motherboard that had a 4 pin cpu fan slot. However, the cpu fan from the last computer only had room for 3 pins; it still plugged in. However, the second the computer starts up, it's loud as fuck. It's consistent, it's not changing the fan speed based on temperatures indicating it's not a heat issue (at about 32 C temperature it should not be running this fast anyways).

    I think it has something to do with mixing the 3 pin fan with the 4 pin motherboard clip; it seemed like there was no other way to plug it in, so would I have to invest in a new cpu fan to fix this or was I able to shift it down a pin to fix this?
     
  2. Originality

    Originality Chibi-neko

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    IIRC, normally the third pin is for reading the fan speed and voltage control. I never did find out what the fourth pin is for. If it's not reading the speed properly or if BIOS has been set with an over-protective CPU fan profile, then that can cause it to run at full speed all the time.

    In my head, when I hear "loud CPU fan", I always read it as "time to get a new CPU fan". Arctic Freezer are great in that respect.
     
  3. Lanlan

    Lanlan GBAtemp Advanced Fan

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    I always thought the fourth pin was a fan speed controller. But I could be wrong.
     
  4. Originality

    Originality Chibi-neko

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    If you need 4 pins for all speed-controlled fans, how would the motherboard (or fan controllers) control the speed of the case fans, which usually come with 3-pin connectors.
     
  5. Zetta_x
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    Zetta_x The Insane Statistician

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    ^^ That and the fan worked dynamically in the HP motherboard (only has 3 pins). I have been wanting to upgrade my cpu fan for a while; nothing fancy as within the next few years I'll probably give this to my brother and build another computer.
     
  6. chains_of_androm

    chains_of_androm GBAtemp Regular

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    Get speedtemp, you should be able to manipulate fan speed that way.
     
  7. Armadillo

    Armadillo GBAtemp Psycho!

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    4th pin is the pwm control signal.

    4pins= fan speed is controlled by pwm. 3pins=fan speed is controlled by voltage.

    Some boards have bios options to tell it whether you are using a 3pin fan on the header and to use voltage control on it or whether it's a 4pin fan and to use pwm control, some even auto detect. I don't believe Asus bios has the option. My 990fx sabertooth which is one of their higher end boards does not have it. Stick a 3pin fan on the 4 pin cpu header and you get no control.
     
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