Why Does A Computer Overheat?

A computer relies on several key components to function. Unfortunately, most of them generate heat. We will look into each component to answer why they overheat and explain why and how to fix it.

A computer overheats from insufficient internal airflow. The external temperature is too hot, one or more components are not cooling effectively, or some parts are overworking. Faulty components generating too much heat can be attributed to insufficient cooling, general failure, or age.

Overheating causes many issues, including poorer performance caused by CPU throttling. Not to mention using more power too.

Some other symptoms include:

But for now, let’s look at some causes in more detail.

Why does a computer overheat?

Why Does A Computer Overheat?

Firstly, we will cover why desktop PCs overheat. Then, after running through all the reasons and their respective fixes, we will cover why laptops overheat.

Internal airflow is insufficient

Here are the most likely causes for the lack of airflow inside a computer case.


a cpu cooler heatsink clogged with dust

Dust is usually the culprit for a computer with degraded airflow. This is an obvious and easy fix.

Take some compressed air, whether from a can or a proper full-sized air compressor, and use it to clean out the inside and outside of the computer.

Don’t be afraid to use a small brush to help with cleaning.

Ensure each component is dust-free, not just the fans and intake vents or filters.

Caution: Make sure the computer is unplugged and taken outside before considering the cleaning process. Also wear a protective covering that you don’t breathe in the dust. Eye protection is also important.

Faulty fans

cooling fans for a computer

After some time passes, coupled with dust deposits, fans tend to spin slower or even stop spinning completely. This is especially true if they aren’t being maintained.

Sleeve-bearing fans are the most susceptible to wear and tear. Fans can seize up to various levels of severity.

If you spin a fan with your finger (first unplug it), watch how it rotates and comes to a stop. If it stops suddenly, it’s not spinning as freely as it should and should be replaced.

Some prefer pulling the fan apart and servicing it, but I’d recommend against it. Replacing the fan is fairly cheap and a sure way to fix the problem.

A more thorough test requires a software program or BIOS to set the fan to 100% to ensure it spins up well enough to provide adequate cooling.

It should reach similar RPMs as listed on the product page of the specific fan model from the manufacturer’s website.

Not enough fans

a cooling fan for computer case

For most computers with a mid-tower or larger case, a minimum of three fans should be present.

Ideally, five fans or more are recommended.

For small form factor cases, be careful. Some have poor designs that don’t allow one large enough fan for proper cooling.

In this circumstance, I recommend replacing the case with something better.

You at least want one good 80mm fan or better to ensure proper airflow for a small form factor computer case.

Fans aren’t configured correctly

a fan with close up of directional markings

I’m sure you already know this, but fans blow air in one direction.

If you have fans working against each other, not moving air through your case, air will become stale, and parts will overheat.

Make sure that you have enough fans placed in such a way as to draw enough air in and move enough air out.

Fans are marked with small arrows to indicate the blade rotation and airflow direction.

If you want to know more about how to do this, please read our article covering PC airflow configuration more in-depth.

Also, check that the CPU fan or fans blow air through the CPU cooler in the same direction as the airflow inside the case.

You don’t want the CPU cooler’s air to flow against the flow of the inside of the computer case causing interrupted airflow.

Fans aren’t spinning up fast enough when the heat rises

fans spinning inside computer

This is a serious problem that can be harder to pick up on. You think your computer is being cooled enough, but it isn’t.

You must hear fans increasing speed when you game or put your computer through its paces.

This is true for case, CPU, and graphics card fans.

This is referred to as a fan speed temperature curve. As heat increases, so do your fans, resulting in more air being used to cool your computer.

Typically, fans are controlled using your BIOS or by software.

Software is usually used when using fan controllers to power your fans.

While this can be true for fans plugged into your motherboard, it’s more common them to be controlled using your BIOS instead.

If this is how your fans are connected, enter your BIOS and set the fan profiles to cool more aggressively.

If your fans are controlled by software, select a different fan profile for each fan to ensure more aggressive cooling.

The room is too hot (Open some windows)

The external ambient temperature plays a big part in how hot your computer gets.

For example, where I live, it gets very humid and hot, making cooling difficult.

In such a situation, ensure you get the room cooled down adequately before using your computer.

Opening all windows and doors is an obvious first step. Try cooling fans, a larger computer case, and an air conditioner from there.

Invest in a larger computer case

My personal desktop computer.
My Personal Rig

Sometimes, after trying everything, you can’t seem to get your room temperature down enough, or you’ve maxed out the fans in your case, but your computer still overheats.

I’ve been there. In this situation, I recommend a larger case.

Having larger spaces around the components inside your computer helps a lot.

Also, you will now have more room to add more cooling fans.

I’ve conducted my own experiments and found that a larger case dramatically helps keep your machine cooler.

One easy way to determine whether or not a larger case will solve your problem is to remove the case lid and turn your computer on.

Use it and observe the difference between the temperatures of each component. A larger case will most likely help if you see a positive result.

Individual components contributing to overall heat

Now we will look at why components get hotter than they should, making your computer’s temperature warmer.

If you have taken care of the above causes of a hotter computer, you can narrow things down by looking into these individual causes.


a cpu getting hot flames added for effect

The CPU is a typical component that generates heat inside it.

It relies on good quality cooling products to deliver the best performance without generating too much heat.

Important: Please remove any overclocking before trying to diagnose overheating issues.

Replace an outdated CPU

Make sure that your CPU isn’t too old and overworking. It could be struggling to keep up with the workload you demand.

Check that the CPU usage doesn’t stay in a high percentage usage range most of the time by opening up Windows Task Manager and selecting CPU under the performance tab.

If your CPU is struggling, you might want to consider an upgrade.

Temperature check

You can check the temperature of internal hardware components using software like HWMonitor.

You can use your BIOS to check the CPU temperature, but it takes time to restart your computer and enter the BIOS.

It’s best if you use software so that you can monitor it in real-time.

If your CPU is reaching unhealthy temperatures while having a cool ambient temperature, it’s time to replace your CPU cooler.

I recommend avoiding stock CPU coolers and opting for a good-quality third-party cooler.

If you’d like to take cooling even further (if your case has the space), you can look at an all-in-one cooler.

It’s a closed-loop cooler that doesn’t require much maintenance but offers exceptional cooling.

Graphics card

a graphics card placed upright on a table

Some graphics cards generate a great deal of heat. High-end graphics cards will produce a substantial amount of heat in your computer.

Important: I highly recommend removing any overclocking on the GPU in order to deal with any overheating issues more efficiently.

If you have a reasonably new card, it’s most likely that the cooling on it should be sufficient, and you should look into other causes like the case size or airflow.

However, if these external factors are in check, and you believe your graphics card is the culprit as a stand-alone problem, I recommend you upgrade the GPU cooler.

There are four main solutions I can suggest:

  1. Replace the thermal compound on the GPU.
  2. Check the fan speed profile.
  3. Replace the graphics card cooler with an aftermarket air cooler.
  4. Replace the graphics card cooler with a liquid-cooled model.

Again, check the temperature using software like Open Hardware Monitor.

Install MSI Afterburner and ensure a good fan temperature speed profile is set. It is a useful software program that will help with most makes and models of graphics cards.

Tip: Make sure that you set it to start up when Windows starts up.

We cover more of that in our article about speeding up graphics card fans.

Power supply unit (PSU)

a computer power supply on a table

Sometimes a PSU can run hot. Ensure your system’s power supply isn’t too old or underpowered.

By upgrading components in your machine, you can soon forget whether or not the power supply can keep up with power demands.

Also, check that the power supply’s fan spins up when generating some heat. Fans in power supplies don’t usually spin up until the power supply produces enough heat.

If your power supply is getting past the five-year mark, consider replacing it to keep the rest of your parts running optimally.


a closeup of a computer motherboard

Sometimes, a motherboard can generate heat from onboard components like the chipset.

If you notice parts on your motherboard getting hot, replace the thermal paste on the heatsink that keeps that part cool.

Some components won’t have heatsinks, so consider replacing the motherboard if it’s getting old and the components are getting hot.

Old hard drives

a stack of hard disk drives for a desktop computer

I recommend conducting SMART checks if you have a stack of hard drives running inside your machine.

Download an app called HDD Scan and install it onto your computer.

If the temperature of these drives is higher than normal, they can generate substantial heat inside them.

If this is the case, consider replacing them and reducing their quantity by purchasing larger drives.

Or even better, invest in a NAS device and some new drives to offer easy access to all your files across all devices.

SSDs Are a fantastic choice if you don’t require large storage volumes.

Reasons why laptops overheat

Now let’s look into why laptops are overheating and how to keep them cooler.


clogged dust in a laptops cooler being cleaned

This can creep up on you without warning. Some months or a year goes by, and your laptop is overheating.

By overheating, I mean slightly or by a lot.

Dust settles in the cooling system of a laptop. As it draws in air to cool the CPU and GPU heatsink, dust accumulates over time and eventually impedes the cooling of these heatsink assemblies.

Laptops rely on complex cooling, which comprises a cooling block attached to the CPU or GPU and then relies on heat pipes that transfer the heat to a finned section where the air from the fan cools the fins down.

When the dust settles in this area, cooling becomes less effective, causing the laptop to overheat.

Taking it in to have it serviced once a year is highly recommended.

If you are capable, dismantling it to blow out the dust yourself could be a way to go. But I don’t recommend doing this unless you are confident in your abilities.

You’re using the wrong power adapter

a power adapter for a laptop

An underpowered laptop power adapter can cause overheating. It can also cause other malfunctions.

It can happen if you have multiple laptops and somehow got the power supply bricks swapped accidentally.

Check that you use the correct one for your laptop and ensure it isn’t over five years old.

Make sure it can breathe

 a laptop cooling pad

Using a laptop on a bed or directly on your lap isn’t the best idea.

There are small vents that the cooling system relies on to be free from obstruction to draw in enough air to cool the parts inside.

Use a laptop cooler instead or some other laptop table that you can purchase to enable you to use it in bed safely.

Stay out of direct sunlight

a woman using a laptop in direct sunlight

If you want to kick back beside the pool while using your laptop, ensure you are in the shade. Operating your laptop in direct sunlight will cause overheating.

It will be very bad for the laptop’s battery, and the overheating will result in CPU throttling, leading to a slow laptop.


These are my reasons why a computer would overheat. Establishing the cause and using my solutions will help you keep it cool.

You will most likely use less power, and it should operate more efficiently and speedily once you get it run cooler.

Don’t be afraid to run tests for some time to get to the bottom of the problem. It may not always be an obvious issue to fix.