How to control CPU fan speed

Controlling CPU fan speed is crucial.

Photo by Erik Gazi

One of the main reasons a PC overheats is internal fans not operating at required speeds. This is often due to the automatic fan controller not functioning correctly. Luckily, you can adjust your fan speeds manually using a few different methods. Manually adjusting your fan speed is also an essential step in overclocking a CPU. This guide covers how to manually adjust your CPU fan as well as any other case fans.

Fan types

Before making any adjustments, you’ll need to check what type of fans you have. CPU fans will always be adjustable, but other fans in your PC may not be so flexible. The easiest way to identify a fan is to check the connector. There are three types of fans: Molex, DC, and PWM. 

Molex fans

Molex fans are characterized by their flat four-pin connectors and their direct connection to the power supply. Unfortunately, because these fans bypass the motherboard, Molex fans are impossible to adjust manually.

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PWM and DC fans

On the other hand, you can manually adjust the two remaining fan types, which are DC and PWM. To spot a PWM fan, look for a connector that is small, four-pinned, rectangular in shape, and plugs directly into the motherboard. 

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DC fans are almost identical to PWM fans with one exception. DC fans have a three-pin connector instead of a four-pin. The extra pin in PWM fans makes them more power-efficient, giving the fan better performance. That being said, you can adjust PWM to run in DC mode, but it’s not recommended and is a downgrade in most cases.

How to adjust fan speeds using your UEFI

The best way to adjust your PC’s fan speeds is through the Unified Extensible Firmware Interface (UEFI). Of course, every UEFI is different, but the steps listed below are similar on every motherboard.

  • Reboot your computer and enter the UEFI. 
    • To enter the UEFI after restarting, look for directions on your boot screen that detail what key to press to access the UEFI. Most commonly, the F2 or Del key will do the trick.
  • In the UEFI, locate the setting in the main menu called Smart Fan Mode, Manual Mode, Qfan Control, or something similar. 
    • You’ll know you are in the right place when you see a list of fans and a curve graph.
Screengrab via Nichoas Wilson
  • Once you’ve located the fan curve graph, choose the fan you want to control and change the Fan Mode to Manual. 

The fan curve can look confusing at first, but it’s simple once you get the hang of it. On the left side of the graph is a number denoting the fan speed, and below the graph is the temperature in celsius. When the temperature inside the case reaches the designated temperature, it will cause the fan speed to increase.

Screengrab via Nichoas Wilson
  • Now, edit the dots on the fan curve to get your desired fan curve.
Screengrab via Nichoas Wilson
  • Save your settings, and reboot your computer. 

How to adjust fan speeds using software

If you use an older PC without a UEFI or want a more straightforward solution, you can use third-party programs to achieve the same effect. The program used in this tutorial is SpeedTemp. However, programs like SpeedTemp may be unable to access your CPU fan depending on your motherboard manufacturer, so using the UEFI is superior in many cases.

  • Open SpeedTemp, and click the Configure box on the top right.
Screengrab via Nichoas Wilson
  • In the configuration menu, head over to Fan Control.
  • Check the box next to Advanced Fan Control. 
  • Click on the Add box located on the right.
  • Name the Fan Controller the group of fans you want to adjust.
  • Select Controlled Speed.
Screengrab via Nichoas Wilson
  • In the drop-down, select the fan you want to adjust.
  • Pick Sum of Speeds. 
  • Click Add under Temperatures, then add the Temperature Probe for the hardware.
  • Adjust the graph to your liking.
  • Click Ok, then go back to the main page.
  • Disable Automatic Fan Speed. 


Once you’ve set your fans to your desired speeds, you should check them to ensure everything is working as intended. The simplest method to check is to use the UEFI. To do this, open your UEFI and head to the Monitor section. From here you can inspect the fan speeds and temperature.

Screengrab via Nichoas Wilson

For more advanced testing, like monitoring a CPU under load, you can employ a temperature monitoring tool. A helpful tool for monitoring your PC’s temperature and fan speeds is Open Hardware Monitor.

Screengrab via Nichoas Wilson

And if you want to see how your PC reacts under stress, you can run a multi-core test in a benchmarking tool, like Cinebench, while monitoring the temperatures and speeds with Open Hardware Monitor.