Computer Fans & Controller

Fans are very important in computers; they are used to cool the CPU, GPU and sometimes the hard drive also. I used to think they cool the devices by blowing the heat away, in reality, they move air at fast speed toward the devices. The propeller ranges in sizes, the greater the size, the more air it displaces but more noise is made. My CPU fan is 120mm and my GPU fan is 90mm.

Fans uses different connectors depending on their use. CPU fans use KK-254 4 pin connectors, chasis fans also use KK-254 but 3 pins connectors or the MOLEX connector and GPU fans use a smaller version of the KK-254 4 pins connectors.

fan-connectorsThe 3 pin fans’ pins have the following use:

  • Black Wire – Ground
  • Red Wire – 12V or 5V power supply
  • Yellow – Tachometer

The 4 pin fans’s wires have 2 color sets while the MOLEX connector only provide power therefore the fans rotate at maximum speed.
PWM Colors

The tachometer reports the number of revolutions per minute. In a PWM fan, the fan is constantly supplied with 12V and the PWM wire is is used to adjust the fan speed. However in a 3 pin fan, the fan speed is changed by changing the voltage.

Fan Controllers

Fans tend to be noisy sometimes. You can try to clean the fan and the heatsink allowing the fan to rotate at a slower speed or use a fan controller to manually control the fan speed.

I bought the fan controller “Thermaltake Commander F5” to control my chasis fan and an old CPU fan which I use as a regular fan during summer. The fan controller was MUR 800 and it can control up to 5 fans. The fan speed of connected fans can be changed by a slider.


  • The range of power supplied ranges from 4V to 10.5V, as a result, you can’t turn the fan off and you can’t adjust the fan to maximum speed since many fans use 12V.
  • One of those blue LEDs stopped lighting after 1 month of use.


  • Up to 5 fans can be connected.
  • Affordable.
  • Color matches with nearly every chasis.

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