Why Does CPU Fan Make Noise? (10 Reasons & Fixes)

Once your PC’s (Personal Computer) fans start making rattling noises, it becomes necessary for you to take action.

Act immediately to figure out and resolve why your system’s fans are making this noise, since most reasons are directly linked to your computer’s components.

Not only will this enhance your CPU’s (Central Processing Units) performance, it will also increase its lifespan.

10 Reasons Why CPU Fan Make Noise & The Fixes

Why Does CPU Fan Make Noise

Your CPU fan keeps it cool by blowing air through its heatsink, and this action only produces a small constant humming noise.

However, in some cases you might hear loud noises from your computer and start wondering why CPU fans make noise.

Read on to know reasons why your system’s fans are making loud noises and how you can easily resolve such issues at home.

1. Dust

Dust in your surroundings is never a good thing, especially if you are surrounded by electrical gadgets, like computers.

Regardless of how much you try to protect your PC from becoming dusty, dust accumulation is bound to occur.

Dust accumulation is inevitable despite keeping your desk clean, because even when you shed skin cells, they spread into air as dust.

Additionally, your PC’s fans enable air flow, which simply translates to your computer pulling dust into its environment. Even though air flows out of your PC, all dust that has managed to enter might not exit this way.

Your system’s fans spin faster and become noisier when dust starts accumulating in it.

Not only does dust obstruct fan movement, it also coats all surfaces of your system, making it difficult for heat to dissipate through any metallic surfaces.

If you smoke around your computer or own a pet who enjoys playing around you while you work, dust accumulation increases significantly.


First you need to prevent dust from entering your computer, which in turn will make cleaning it up easier. Install protective filters on all vents and fans on your computer’s outer frame.

These filters prevent large particles of dust from entering, so you need not worry about your pet’s hair or larger dust particles obstructing in any way.

These outer filters must also be cleaned regularly once every one or two weeks.

If you are allergic to dust you might want to put on protective goggles and a mask before opening up your CPU case’s side panel.

Dry dust can be simply removed with a duster, however, to remove layers of grime, you will need either a paper towel or microfiber cloth covered in isopropyl alcohol.

Do not use any other type of fluid for cleaning as they might leave traces of moisture behind. This moisture is dangerous for your computer as a whole.

Even if you spray isopropyl alcohol onto any one of your PC’s internal components, by mistake, it will dry up by itself and not leave any moisture behind.

Hence, no other form of fluid cleaning agent must ever be used to clean your computer.

Also, use a cotton swab or a small paint brush to clean up fans, crevices and difficult to access and clean corners of your computer.

2. Poor ventilation

Your computer’s ventilation system must be working effectively. As, restricted air flow contributes to several severe problems.

Initially, poor ventilation only affects your CPU’s performance by slowing down its processing speed. If you do not notice this issue and resolve it immediately, it will eventually lead to regular overheating of hardware.

Overheating reduces the life of your hardware by increasing wear and tear, which then results in complete system failure.

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In order to protect itself from further damage your computer slows down purposefully, as doing so makes it easier for it to cool down quickly.

Other causes of poor ventilation are accumulation of dust in and around your computer, internal or external obstruction around air vents and improper conditions of PC placement and storage.

Due to poor ventilation fans are forced to operate faster and so they increase their speed of spinning in order to quickly dissipate heat.

This is what causes fans to produce loud whirring/clicking noises.


Your PC’s air vents must be cleaned in a systematic manner, so follow these steps to ensure ventilation is restored to 100%.

  1. Start by turning off your computer and unplugging it from its power source.
  2. Next, check your system’s vents from outside as well as inside. Accumulation of dirt and dust in and around vents is probably clearly visible.
  3. Then, purchase a can of compressed air, remove dust filters and start blowing air into your computer to clean air vents and fan fins. Dust filters can be cleaned under running water and dried separately.
  4. If necessary, you can open up your computer and clean inside as well, if it hasn’t been cleaned for a month or two.

When following these aforementioned steps, you need to follow certain guidelines in order to ensure that your computer is not damaged further.

  • Vacuum cleaners and blowers must not be used as they can damage your PC through static charge. If you have no other option you need to ensure all devices being used are earthed, and you are also grounded. Do not let any components of either device come into direct physical contact with each other.
  • If you have no other way to blow air to clean your system’s vents, do not consider blowing air through your mouth. Not only is the pressure insufficient when you are blowing air in this manner, but doing so might also damage your computer in case moisture from your breath comes into contact with any internal components.
  • While using compressed air to clean vents, carefully follow usage instructions of your compressor or those listed on a compressed air can.

3. Malware infections

Malware, worms and viruses are among the most difficult to resolve issues your computer will face. Sometimes, they slow down your computer, and sometimes they speed it up to 100%.

While slowing down its processor does not cause any permanent damage to your computer other than hindering you from getting your computer related work done in time.

Speeding it up can, however, cause numerous problems including overheating and permanent hardware damage.

Once malware infects your system, it not only takes a significant part of your memory but also starts consuming CPU resources.

Then it starts infecting more files, removing original data and filling up space with corrupted data, consequently consuming more resources and space.

Since, a virus or malware’s motive is to damage your computer, it starts this by damaging data and by making your CPU work much harder than it usually does.

This makes its fans move at high speeds, and make loud noises, while trying to cool down your processor.


Install and/or update an antivirus or anti-malware software, as they not only get rid of corrupted files but also all traces of virus and malware.

4. Corrupted processes

Corrupted processes often make CPU fans work harder and create loud noises as if they are malfunctioning.

These processes are unable to access the right number of resources and proper space in computer memory and as a result end up adding to your CPU’s stress.

These unnecessary processes must be stopped immediately, as they might be consuming up to 100% of your CPU’s processing power.


To close excess or unwanted processes which consume power needlessly Windows users must click Ctrl+Esc+Shift or open Task Manager.

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It shows all applications and processes running currently. This makes it easier to monitor and determine which processes are unwanted and can be ended immediately.

For those who are encountering this issue on Mac, you must first access the Activity Monitor window by clicking on Ctrl+Space.

Then, you must end all processes that you feel are unnecessary and are straining your CPU’s resources as well as your memory.

Also check for overheating with dedicated tools used for measuring CPU temperature to check for any signs of overheating.

Such tools inform when temperatures are higher than average. They make it easier to determine exactly when to start closing unnecessary programs.

5. Improper placement

Your computer’s placement and surroundings play a major role in keeping it cool.

If your computer is placed in an enclosed space while running, as expected, it causes your system to overheat. As these obstructions prevent proper airflow to and from your system.

When your computer overheats due to being placed in enclosed surroundings, it automatically makes its fans spin faster.

As your entire system starts focusing on cooling down as quickly as possible to avoid permanent hardware failure.

Oftentimes computer users put no thought into where they place them. Placement decisions are made based on convenience rather than a computer’s overall health and optimal functioning.

In simplest terms, places where air cannot circulate freely are unsuitable for placing a computer.

This in no way means that computers must be placed near windows to facilitate proper airflow, as placement close to windows comes with its unique set of problems and challenges.


Start by choosing a proper place for your computer, with proper air flow. This area should be cool by itself as well as mostly clean.

Placing your computer next to a window is not advisable as doing so can heat your computer much more quickly due to direct sunlight.

Do not choose enclosed spaces where walls or furniture are obstructing air flow. Your system must always be placed on an even and flat surface.

Employ an external cooling system for your computer in case you do not have a cool environment.

Also, add rubber feet below your CPU’s case. This makes it easier for your CPU’s case to cool down quickly, by increasing air flow around your system as well as surface area to dissipate heat.

Keep checking these rubber feet from time to time to replace them as soon as they start becoming worn out.

6. Overclocking

Overclocking is a process which forces your CPU to work at speeds higher than what is approved by its manufacturer.

It often results in your computer overheating and requiring fans to function at higher speeds. Overclocking must be avoided if possible as it does not increase speed significantly in all cases.

Also, overclocking voids warranty as it is not a safe process to make your CPU work better. Most individuals who attempt to overclock their system are unaware of how complicated this process is.

Furthermore, if your CPU does not have a proper cooling system in place be careful while overclocking.


You must avoid overclocking your CPU if your RAM (Random Access Memory), and permanent memory are slow as it causes bottlenecking.

If you do want to overclock, learn the entire process properly and also find proper settings for your particular CPU model before attempting.

Also, increase CPU speed by one or two units only, to achieve optimal results.

To reverse or remove overclocking, reset to factory settings through BIOS settings or download a dedicated program for overclocking and change CPU clock values.

7. Outdated drivers and BIOS

Your new computer is set to automatically download BIOS and driver updates, as it keeps your software up to date and compatible with your hardware.

Over time, you need to stop these automatic updates because once your hardware becomes old, new drivers increase incompatibility and cause CPU to become strained.

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Fans start spinning faster when your CPU is strained, as they put in extra effort to cool down excess heat generation.


Find previous driver versions which were compatible with your system and download them.

You need to install drivers for the video card, chipset, thermal chipset and BIOS.

8. Fans hitting side panel

GPUs, (Graphics Processing Units) when purchased independently and installed in an existing system might not fit into the CPU case completely.

When this happens closing your CPU’s side panel becomes difficult, as your GPU fans keep hitting your CPU’s case. This makes loud rattling noises as your system’s entire frame is being shaken up constantly.

Keeping your CPU case’s side panel open is not an option as it will increase and accelerate dust accumulation, which in turn will obstruct fans and result in loud noises.

Your system is designed to operate in a certain manner, so when a side panel is removed, it disrupts air flow.

This disruption in air flow might cause uneven cooling, which may lead to damage in certain components of your computer.

Components closer to the open side panel cool down quickly but are likely to get damaged due to excessive dust accumulation.


This issue can be resolved in two ways depending upon your budget. If you are willing to spend more you can purchase a bigger case for your CPU.

This allows all components to fit in their proper places without being cramped. You can also install additional fans to enhance cooling as a bigger case has more space for fans.

In case you do not want to spend much, you can get a small rubber or foam sheet. Stick it to the detached side panel’s inner surface and close up your system.

This ensures fans do not come into contact with your CPU case’s internal surface.

Do not choose a thick layer of foam/rubber sheet, as it might increase pressure on the GPU and force it to dislodge from its dedicated slot.

9. High-end graphics

CPU and GPU are the two components of your computer which produce maximum heat.

When being used optimally, these components generate a lot of heat, which in turn might lead to overheating if their fans are not working properly.


Check if all fans are working properly or if it is just one fan close to your CPU or GPU.

If only one fan in your system is making noise, try determining any underlying reasons for this issue and replace this fan accordingly.

You may want to consider adding an extra fan or cooling system if all fans are creating these loud noises.

10. Faulty fans

If you have checked for all reasons mentioned above and haven’t been able to solve your system’s fans’ rattling/whirring noises then it is nothing but a hardware defect.


Try using machine oil as it works in some cases and allows fans to spin and function easily after being lubricated.

If your system fans still do not run smoothly even when your system is idle, you need to replace these fans, as they cannot be repaired.


Fans are not the only component which can make these clicking/rattling/whirring noises in your computer.

Your hard drive also makes whirring noises continuously, especially if it is close to failing permanently.

Determine using these aforementioned causes if and why the CPU fan makes noise.

If it is not your system’s fan but your hard drive, you must have your system inspected by a technician.

About Puja Chatterjee

Puja ChatterjeePuja Chatterjee is a technical writer with extensive knowledge about computers. She graduated from BIMS. Her expertise includes technology writing and client relationship management gained through over 12 years of experience. Follow Her at Linkedin.

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