How to Adjust a Case Fan Speed

By Matthew Smith

Adjusting a PC case fan
i power supply cooler image by Galyna Andrushko from

Although many people don't think about them, case fans are an incredibly important part of the modern computer. Because the components in modern computers are so powerful, they produce a lot of heat. Heat is bad for computer components, so it is important to quickly whisk the excess heat away from the components and out of the computer's case. You can change the speed of the fan to increase its effectiveness.

How to Adjust PC Case Fan Speed

Download and install the SpeedFan utility. SpeedFan will automatically detect all case fans currently connected to the computer's motherboard and display their operating speeds. SpeedFan will also show the current operating temperature of the computer's processor and other core components so that it is possible to see the effects of adjusting fan speed in real time.

Use SpeedFan to adjust fan speed by using the speed adjustment buttons near the bottom of the program's main menu. The current RPM speed of the fans being adjusted is displayed in SpeedFan and will change depending on how the speed is adjusted in the SpeedFan utility. If the fans are responding to commands from SpeedFan, no further action is required to adjust them.

Shut down the computer and open the case to gain access to the computer's internals. Look inside the case to see if there are any fans beyond those that appeared in SpeedFan. Check the additional fans to see if they have a wire that can connect them to the motherboard. This wire will be thin and will end in a three or four prong female adapter. If such a wire is found, plug it into the motherboard (refer to the motherboard manual for the proper location). The fan should now respond in SpeedFan.

Check any fans without a motherboard connection wire for a manual adjustment switch. Look for a small switch connected to the fan by a thin wire. Fans with a manual switch typically have three settings, from low to high. The medium setting is often the best compromise between noise and cooling. If no such switch is found, and no motherboard connection wire is present, the fan is not adjustable.