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3 pin cpu fan speed control with 4 pin motherboard

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Last response: in Components
September 21, 2012 7:08:14 PM

I recently replaced the motherboard in my friends computer (the SATA controller was bad) with a foxconn A88GMX motherboard. The CPU heatsink and fan is a 3 pin connector. When I connected this to the motherboard 4 pin PWM header the CPU fan runs at full speed (like 4200 RPM) all the time and is very loud. I checked the BIOS for options to control the fan speed (manually or intelligently temp based) but it seems to only have options for a 4 pin fan. The motherboard came with a program called Fox One that looks like it has setting for fan controls in the manual, but whenever I try to run it, it says "This program does not support this model." Is there anyway for me to control the fan speed with this setup?

More about : pin cpu fan speed control pin motherboard

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a c 117 à CPUs
a b V Motherboard
September 21, 2012 7:10:09 PM

You need a fan controller, 4 pin fans use PWM to control speed, 3 pin use voltage.
September 21, 2012 7:14:00 PM

So I'm assuming that the replacement board does not have options to control by altering the voltages... if a fan controller is my only option (besides replacing the fan and heatsink with a 4 pin connector) Do you have any recommendations for a budget controller?
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September 22, 2012 3:49:34 PM

Best answer selected by rebelj.
April 27, 2015 7:38:42 AM

Hi everybody. I have my doubts about a 3 pin fan speed variation: I have conected a rear fan to a 4pin mobo conector (called "cha_fan", it would be chasis fan - in other mobo´s it is called sysfan) and watching its speed throw "HW Monitor" it usually goes at 1100rpm, but when y play a game it goes up to 1900. So, my question is how the 3pin fan can change its speed if it has not the fourth cable (pwm)? I also have a 3pin fan into the cpu_fan header and it is always at the same speed (2100rpm); no variation speed!! Don´t understand. Thanks