CPU fans are crucial in preventing your PC from overheating. If your CPU fan doesn’t work properly, your processor will overheat, and the rest of your computer will be negatively affected. Fixing a twitching or otherwise malfunctioning CPU fan is essential for PC longevity.

1. Your Computer’s Motherboard Is Malfunctioning

The motherboard is responsible for operating all the parts in your PC apart from the power supply. If the motherboard isn’t working properly, you’ll notice many issues. These errors could range from twitching CPU fans to random restarts and more.

Most computer motherboards last a long time, but improper air circulation, electrical wiring issues, and old parts can take a toll on the PC’s motherboard. Once the motherboard stops working, the CPU fan will twitch and fail.

You will often find the computer won’t boot or start up when the motherboard is the cause of the problem.

Your Motherboard Has BIOS Errors

Check the PC BIOS to know how your CPU fans are running. For example, if they’re twitching, they should be at 0 RPMs. If the RPMs look normal in the BIOS, there may be something wrong with the CPU fan’s wires, the motherboard, or the BIOS.

There are many solutions to these issues, so let’s dive into everything you need to know below.

How To Correct BIOS Errors

Try this method to look for BIOS errors:

Access your computer’s BIOS settings. You can access most of them through the startup menu.
Click on the cooling or circulation menu, then look for the CPU fan’s speed and the PC’s temperature.
Increase the fan’s speed and check if your CPU starts to work. If it doesn’t, the fan is likely damaged and needs to be replaced.
If the fan speed increases, your computer might have malware that affects the BIOS and alters the CPU fan speed.

BIOS errors are relatively uncommon, especially if you update your operating system and computer. I recommend manually checking for updates in your computer’s settings menu every month or so.

2. The Power Supply Is Faulty

A faulty power supply is one of the most common reasons a CPU fan twitches without spinning completely.

The power supply is also responsible for operating many other components in your PC. If anything else isn’t working like it should (in addition to the twitching CPU fan), there’s a good chance something’s wrong with the power supply.

When the power supply is the cause, the computer often won’t post or start up as the motherboard won’t function properly.

Before replacing either part, check the connection between the power cable and the power supply.

How To Deal With A Faulty Power Supply

Here’s how to replace a broken power supply and fix your twitchy CPU fan.

Turn off the computer and unplug it from the wall.
Remove the computer’s side panel to expose the motherboard.
Disconnect the power supply cables from the motherboard. They’re usually tied together, so you should remove them by unclipping the main wire.
Remove the wires connecting the power supply to the hard drive(s) and set them aside, ready for the new power supply.
Remove the retaining screws and pull the power supply out of the computer.
Slide the new power supply unit into place.
Connect the hard drive and motherboard wires to the new power supply and secure the retaining screws to the power supply and the PC.

When you’re done, plug the computer in, turn it on, and check your work.

3. There’s Excessive Debris On The CPU Fan

All computer fans eventually get covered in dust and grime. They’re constantly spinning, which attracts tons of debris that can get stuck in the blades and bearings.

If you don’t remove the debris, the fan will lock and be unable to move. The fans will start twitching, and then they’ll stop working altogether. The good news is that this is one of the easiest issues to fix if you catch it before it damages the CPU or the fan.

How To Clean The CPU Fan

Here’s how you can remove the debris buildup from your CPU fan to stop it from twitching:

Turn off the computer and remove the cover plate from the CPU fan.
Use a can of compressed air to remove dust from the blades and the base of the fan.
Remove debris from hard-to-reach places with a Q-tip or a pipe cleaner.
Spray rubbing alcohol on a microfiber cloth and wipe the blades to prevent grime and debris from sticking to the fan.

Once you’re done, cover the CPU fan and turn it on. If it still doesn’t work, head to the next suggestion.

4. The CPU Fan Is Broken

Once the fan is broken, all you can do is replace it. Broken CPU fans are caused by many problems, most of which relate to gradual wear and tear. Below, I’ll list a handful of reasons you might have to replace your broken CPU fan:

Your fan is beyond the manufacturer’s warranty and doesn’t work anymore.
The CPU fan is past the manufacturer’s suggested longevity.
Blades or bearings are broken on the CPU fan.
The fan is old, and the bearing doesn’t have sufficient lubrication.
The motor is fried and can’t be repaired.

How To Replace A Broken Fan

Your only solution for a broken fan is to replace it. Follow these instructions to swap out your CPU fan:

Turn off your computer.
Remove the wires and the side panel to expose the processor.
Remove the retaining bolt or bracket from the CPU fan.
Remove the fan and clean the thermal paste off of it.
Apply thermal paste to the plate on the bottom of the new CPU fan and press it against the CPU.
Slide the bracket or bolt through the fan to lock it in place.
Connect the new CPU fan to the motherboard via the provided cable or with the old one if it’s still attached to the motherboard.

5. The CPU Fan Wires Are Damaged

CPU fans have several wires going to the motherboard. They often use a multiport clip that connects to the motherboard without soldering or crimping each wire.

If any wires are bent, stripped, or exposed to copper, they won’t work properly. This incorrect layout could cause the CPU fan to twitch because there’s no steady power supply.

How To Repair Damaged Wires

Damaged CPU fan wires are relatively uncommon (unless you mishandle the PC). However, you can use these suggestions to inspect and replace the wires as necessary:

Replace any of the wires if the copper is exposed or if the wire is bent beyond repair.
Disconnect each wire connected to the CPU fan and check if the clips are cracked or loose. If they are, replace them.
Push and secure each wire clip on the motherboard and the CPU fan to ensure they’re not wiggling or shorting the electrical current.

Note: If you replace the CPU fan wires, contact the manufacturer to get the part number. You can also check the part diagram to ensure you’re doing the right thing. Using the wrong wires will prevent it from working.