How to Control Fan Speed On PC

A computer adjusts its fan speed according to the load it gets. If you are doing some CPU-intensive tasks, your CPU cooler will spin at a higher RPM (Rotations Per Minutes). The same goes for your GPU.

However, you can control your fan speeds according to your needs using third-party applications or tweaking fan settings on your BIOS.

How Does a Computer Change the Fan Speed?

First, let’s discuss how a computer controls its fan speed. Depending on the cables attached, the fans on a desktop PC are connected either to the motherboard or the power supply. You can find three types of cables that connect the fans to the motherboard/power supply. 

• 3-pin DC fan connector cable connects the fan to your motherboard. Fans connected with this cable spins at maximum RPM unless we change the speed from the BIOS.
• 4-pin Pulse Width Modulation (PWM) is also connected to the motherboard. However, it uses the sense pin to control the RPM according to the CPU load.
• Molex Fan Connector connects the fan to your PSU (Power Supply Unit). Fans connected with this cable also spin at maximum RPM. We need a Molex to 4-pin PWM hub to control its speed. 

How to change fan speeds?

Here are a few techniques to change/control the fan speeds.

Controls From BIOS

Any piece of hardware attached to a motherboard will have settings in the BIOS to control it. If you have connected the fans to your motherboard, you can easily adjust its speed with the help of the BIOS. 

Sometimes, the fans on your computer will spin at their maximum RPM. This is because the RPM, by default, is set to maximum on your BIOS (Basic Input/Output system). 

• To enter your motherboard’s BIOS, press the Del or F12 key rapidly
  (If you do not know how to enter the BIOS, please refer to the user manual for your laptop/motherboard).
• Once inside the BIOS, use the arrow keys to navigate through it.
• Search for a Fan Speed Control option. Again, the option displayed will be different according to the motherboard manufacturer.
  

Some motherboards will have a Smart Fan Mode feature in the BIOS. This feature will automatically increase or decrease the fan speed according to the temperature of your system.

If you want to run the fans at maximum speed all the time, you can disable this feature. Once you disable the Smart Fan Control, all CPU and system fans will spin at a high RPM.

Some motherboards will also let you adjust the fan curve that enables the user to set the fan speed according to the temperature.

Fan Controlling Kit

If you do not want to open the application every time you want to change the fan speed, then the fan controlling kit will be your best friend. Using the equipment, you can do this manually by turning a knob.

A fan controlling kit is a physical device that adjusts your CPU and case fans. You can adjust this kit on the front side of the PC case like any CD/DVD drive. The kit will either have a knob or an LED display to adjust the RPM of your fans according to your need. The equipment will also display the current RPM of all your fans.

One downside to this kit is that these kits cannot control the fans connected with a Molex Fan Connector and the GPU fans.

Third-party software

Tweaking the BIOS setting can be a little risky as there is always a chance that your OS may not boot. If you are on a desktop computer and do not want to change the BIOS settings, you can always use a third-party application. These applications will help you tune the CPU and GPU to get maximum performance with low noise.

Please note that you cannot control all fans inside your motherboard. You cannot change its speed if the fan is connected to a PSU (Power Supply Unit) through a Molex Fan Connector. 

However, if the fans are connected to the motherboard, either with 3-pin or 4-pin, these third-party applications can control the fans’ speed with a click of a button. Some of the best Fan Control Software are listed below.

Adjust from Windows settings

This is a simple Windows feature that lets you change the fan speed. You can follow these steps below:

Note: Only desktop users can access this Window feature to change the fan speed. 

1. Press the Windows key and open Control Panel.
   Make sure that the View by option is Large icons on the top right.
   
2. Click on Power Options.
3. Under Choose or customize a power plan, click on Change plan settings.
4. Click on Change Advanced power settings. A new Power Options dialog box will open.
5. Scroll down to Process power management and click the “+” icon beside it.
   
6. Select System Cooling Policy. Then, click the dropdown icon.
7. Now select active from the dropdown menu.
8. Click Apply, then OK.

FAQs

How to Control All Computer Fans Simultaneously?

You can control all computer fans simultaneously using a fan hub. It is a junction-type device that connects all the cables from your case fans. 

How to Control Fan With Molex Fan Connector?

If you want to control the Molex fans (fans with Molex Fan connector) with the kit, you can get a cable that has three ends:

• One end is a 4-pin PWM connector.
• Another one is a Molex connector.
• The final one is connected to the fan.

One end (Molex Connector) of this cable is attached to the PSU, while the other (the 4-pin PWM) is connected to the motherboard.

Can I Control Molex Fan without Any Adapters?

Yes, you can lower its speed by providing the fan with a low voltage. A Molex connector has four pins attached: two ground pins on the center, one pin that provides 5V, and the last one providing 12V.

You can rewire the Molex fan connector to a 5V line instead of the 12V, and this will make your fan spin at a lower rate. However, if the fan doesn’t spin on 5V, connect it to the 12V line.

Can I Convert a 3-Pin DC Fan Connector to 4-pin PWM?

If you want to control a 3-pin fan, you can find adapters that convert a 3-pin DC fan connector to 4-pin PWM.