Why Does CPU Usage Spikes to 100? (8 Fixes)

By Dominic Chooper on December 14, 2022

High CPU usage can lead to damage and decreased lifespan of your computer. It’s important to identify the reasons behind a 100% CPU usage spike and resolve them to protect your system.

This article covers eight reasons for high CPU usage, along with solutions to overcome them.

The reasons include lack of rest, unwanted tasks, outdated drivers, power settings, running too many browser tabs, malware, antivirus software, and outdated operating system.

Read on to learn how to reduce CPU usage and protect your computer.

Why is Your CPU at 100 When Nothing is Running?

In order to determine when CPU usage is spiking or what is triggering it whenever you use your computer, you can start by putting up a CPU usage graph.

This way you will be able to clearly see when CPU usage is fairly high and check what processes are active to determine its cause.

If your CPU spikes to 100% usage again and again it is definitely making it difficult for your system to function optimally.

Read on to determine and troubleshoot why your CPU’s usage is spiking to 100 when there are no processes running,

For instance, programs which start at Start Up. These programs start as soon your computer is done booting up and then they run as background applications.

While these programs are not immediately visible to you on your Taskbar, they do consume CPU power. Therefore, CPU usage graph will show some amount of CPU power being utilized.

Also, some programs remain hidden but use CPU power to download and install their updates.

While small applications do not cause a spike, bulky applications which require more memory space may cause a significant spike in your computer’s CPU usage graph.

All applications and programs, regardless of whether they are running in the background or are hidden, they will be visible through Task Manager.

Task Manager not only displays a list of all current activity but also shows what percent of CPU power each application utilizes.

If you have noticed these signs and want to be sure of your diagnosis, you can ensure this in a simple way.

Next time when you suspect malware is performing any action on your computer open

Task Manager and look up all currently active applications and processes using your CPU’s processing power.

If there are any applications that seem suspicious or any processes which you cannot link back to any known CPU functions, it must be a virus.

Another way of ensuring your CPU’s usage spike is associated with malware is by performing a complete system scan for malware.

However, this method cannot be completely trusted especially if you have found signs of malware infection through Task Manager and a malware scan shows zero threats found.

It might be a new malware, so update your system after a few days and scan again.

Schedule complete system scans for weekends or days when you do not need your computer for several hours, making it easier for your system.

Since, your computer has necessary space and time available for a thorough check without adding to your processor’s workload.

If you are not sure that your CPU usage is spiking randomly because of anti-virus programs, uninstall this program and wait several days to ensure that there are no random, unexplained CPU spikes.

Now install this program again and scan to check if it results in CPU usage spike.

8 Reasons Why CPU Usage Spike to 100 (with Solutions)

Why Does CPU Usage Spikes to 100

Your computer cannot function properly or have a long lifespan, if it is being used in a high-stress situation.

When your CPU’s usage rate is at a 100% for extended periods throughout the day, you need to start focusing on how to reduce its workload, or increase its processing power significantly.

If you do not want to replace your CPU or you entire system after it gets fried, you should read on to find out why does CPU usage spikes to 100.

Then, go through solutions mentioned below to resolve this issue and protect your computer.

1. Lack of Rest

If you are not in the habit of turning off your computer ever, it can result in CPU spikes. Your computer needs to be turned off once every day, in order to refresh its RAM.

When your system’s RAM does not have sufficient memory or speed to support tasks being carried out by your CPU, it increases strain on your system, thus causing CPU spikes.

It also leads to overheating of CPU as well as bottlenecking as your RAM’s and CPU’s processing speed is not comparable now.


Remember to turn off your computer whenever you go to sleep, since your computer needs to refresh and rest.

If you want to leave it powered on throughout the entire night, you need to give your system some break by shutting it down whenever possible.

2. Unwanted Tasks

Multitasking is one of the reasons for high CPU usage, however, if done properly it does not cause CPU spikes.

Even if you do not want to run plenty of applications and are simply studying or working with a single application with music playing in the background, you are using several tools.

This in turn leads to several processes being run simultaneously and increased utilization of your CPU’s processing power.

If you want to multitask with several applications, chances are you are causing a CPU usage spike.

Doing so does not spike CPU usage to 100%, unless these applications you are using for multitasking are CPU resource-intensive.

Generally, multitasking only causes a 70-80% CPU spike, which is not harmful to your computer.

However, using your CPU’s resources like this for a longer period of time, damages it as it leads to overheating, bottlenecking and rapid wear and tear.


The only way to lower CPU usage is completely closing any applications you are not using actively. However, you have numerous background applications which you might not want to or in some cases cannot close.

Uninstalling these apps is also not an option because you installed them as you need them and some of them cannot be uninstalled by you because your system needs them.

In this case you have two options, first is to modify your computer’s power settings and the other is using a third-party tool to control background applications.

Your system’s power mode settings allow you to configure the best power mode for you according to your usage.

However, you can choose to optimize your system and customize these settings to suit your requirements.

If you set it to low power mode, your CPU is then forced to work with lower power, which ensures overheating will not occur quickly.

Additionally, CPU prioritizes essential tasks and applications which are necessary for your computer to keep operating, over resource intensive tasks.

While it ensures all applications and tasks get their turn, CPU usage spike is not possible as all tasks get executed one by one.

There are plenty of free and paid third party applications which enable modification of settings in such a manner that processes which are not being actively used can be put in sleep mode.

Sleep mode does not put your entire system to sleep, but only some particular applications preventing CPU usage spike.

These applications can be chosen according to their power usage or if they are being categorized as background processes.

Some paid versions of free tools might even allow you to choose specific applications that you can put to sleep.

When these applications are put to sleep, they are not shut down, but allowed to remain open without having any access to your CPU’s processing power.

Therefore, CPU usage is kept low even though numerous applications are open.

3. Outdated Drivers

CPU usage spike to 100% is sometimes caused by old or outdated drivers. Drivers are applications which enable proper functioning of some of your computer’s components that are connected to its motherboard.

These applications enable their linked components to be controlled manually.

Drivers become outdated over time thereby giving rise to incompatibility issues. This incompatibility is what causes excessive consumption of CPU’s processing power.


For new computers you must regularly scan for updates for drivers, as latest drivers always assist in improving performance. Additionally, new computers are optimized for performance, as they have very few issues at this stage.

However, do not download drivers as soon as you receive an update of newer versions being available for use.

Some drivers even after being released have bugs in them, which affect your computer negatively and might still continue to increase CPU usage.

Wait for a week or two before downloading any driver update. So that, if there are any bugs in a particular driver, chances are it will have been tracked and rectified.

You can opt to download drivers automatically or search for a driver manually and check its version against one already installed in your system.

Read Also:  7 Ways to Fix Hard Drive Not Spinning Problem

If you do not want to search for updates manually, you can choose to setup a third-party tool which is built for checking if any drivers are old, outdated, incompatible or buggy.

These programs perform regular scans on your system and ask for permission before installing necessary drivers.

4. Software Issues

Some software applications are too bulky and cannot function properly with your CPU’s configuration. Since, they are incompatible it is better if you do not install these applications.

If you have already installed them and your computer is now crashing you should stop turning on your computer for the time being until you troubleshoot.


If your computer is turning on, open Task Manager and check which process or application is causing your CPU usage to spike to 100%.

Try ending this process and then uninstall this  application if it was installed by you.

However, if you are unable to figure out which process or application is actually causing this error, scan your computer for virus and malware.

Consult a local expert to check what is wrong with your computer if your computer is no longer turning on. They will first check all hardware components to detect problems and then start checking for software errors.

If you want to restore your system to its previous functional state you might want to have your system completely formatted.

Choose an OS (Operating System) of your choice and install it yourself or avail services of a technician to have your system formatted completely.

5. Dust

Just like software applications are able to cause CPU usage to spike to 100%, hardware and its maintenance might also be at fault.

Dust accumulation always makes your CPU work harder as your computer has to handle more pressure to perform every task.

Dirt and dust slow down your processors’ speeds and also affect all associated components. Therefore, to keep your system functioning optimally, you need to clean it regularly.

You might not consider your computer’s dusty internal components as a reason for sudden and random CPU usage spikes.

But dust accumulation is often one of the main reasons for most major problems associated with your computer.

When dust covers all internal and external surfaces of your computer and its components, it restricts air flow and prevents heat release.

This in turn slows down your CPU’s processing speed making it work harder to function at normal levels and speeds.

If you have not cleaned your computer properly for a year, CPU usage spike might reach up to 90%.

If it has been several years since you last cleaned inside your computer’s CPU’s case your computer can crash at any moment.

Also, it might not be able to function for longer durations as high CPU temperatures might force system to shut down by itself.

When your computer is strained, and working harder, its CPU usage may spike to 100% and this will lead to definite overheating.

This heat is unable to dissipate quickly because of blocked air flow, which in turn will cause your system to freeze, crash or shut down abruptly.

If you want to prevent permanent damage to your system and want it to run properly next time you turn it on, follow the cleaning instructions discussed below.


You have two ways to remove dust and dirt from inside your CPU’s case.

You can do it manually or by using a vacuum cleaner, however, you need to be careful as your computer’s internal components are sensitive and can be damaged very easily.

If you choose to clean manually, do not use any water-based cleaning fluid as your computer may die due to moisture.

On the other hand, if you choose to use a vacuum cleaner you need to be very careful when using it.

Otherwise, it may lead to accumulation of static electricity in your computer’s smaller components which are particularly sensitive to static charge.

Once static electricity accumulates in them, these components are unable to function properly and are considered completely damaged.

Take paper towels or a microfiber cloth and spray isopropyl alcohol on it to start cleaning your computer manually.

Wipe down all visible dirty surfaces as far as you can reach without removing any internal components from their places.

If there are hard to reach places you might want to use a paint brush with a long handle or cotton buds to clean up crevices and corners.

If you choose to operate a vacuum cleaner it is necessary to ensure all your power outlets are earthed and you are also grounded.

Do not use a vacuum cleaner connected directly to any electrical outlet, as it guarantees accumulation of static charge in your computer.

Use a hand-held model which does not need to be connected to an electrical outlet.

Also, do not come in contact with any other electronic device as it might create a flow of electricity that in turn damages your computer’s components.

6. Overheating

Your CPU generates a lot of heat once it is powered on. This heat generation increases with your CPU’s power consumption as its workload starts increasing.

Your CPU is generally strained with a heavy workload when its usage spikes to 100, which translates to further generation of heat.

Since, this heat does not dissipate as quickly as it is generated, it leads to overheating.

Due to overheating your system might freeze or shut down randomly, experience glitches and become very slow while its fans spin with loud noises.


In order to prevent your system from crashing or freezing, you should always be on alert if you know overheating is being caused by CPU usage spikes.

Open your computer’s Task Manager and set it to always display in front.

This way even if you are gaming at full screen, once your CPU usage reaches 90% you can shut it down, preventing your system from crashing or freezing multiple times.

Once you close applications which are straining your CPU your system can take its time cooling down.

If you have a third-party tool to control these tasks or processes, you might be able to simply pause or put them to sleep so they do not consume any CPU power.

This prevents you from abruptly shutting down applications without saving any data or process.

You must set up your fans to run at top speeds once CPU usage spikes to 100% as fans are required to cool your computer quickly.

However, if you plan on using your CPU with its usage at 100% you must invest in an external desktop cooler.

You can also consider choosing between a wind-based or water-based cooling system, as both are safe and equally efficient in quickly cooling an overheating computer.

You will start experiencing glitches when your CPU’s usage is very high. Combined with glitches caused by overheating, these glitches might lead you to believe your system is infected by virus or malware.

However, you should carefully monitor your CPU usage graph and note when it spikes and when it dips. If these spikes occur only when processing a certain task, you might have to scan this application for virus and malware.

You can also shut down these processes quickly when you know it will lead to your CPU being permanently damaged over time.

If your CPU has turned sluggish, you should give it a break by putting it in sleep mode or turning it off. Try to shut down your computer once every 6 hours if you plan on keeping it on for a whole day.

If you are unable to shut it down due to work, you must shut down background processes from time to time and put your computer in sleep mode so your overheating CPU gets some much-needed rest.

7. Issues Caused by a Single Application

Your computer’s Task Manager might be reporting that a single application is utilizing most of its processing power.


Some applications are known to increase CPU usage significantly, often leading to a CPU usage hike. It is better to remove these applications and download similar applications created by others for the same purpose.

8. Outdated BIOS

This reason should be considered only after you have checked all aforementioned reasons and confirmed that none of them are able to resolve CPU usage spiking to 100%.

Your BIOS (Basic Input/Output System) may be faulty or outdated, which causes your computer to work more even though it does not have a heavy workload.

BIOS is tasked with starting up your computer, conducting pre-startup checks and loading OS. If it is not working properly or causing issues your computer might not be able to start.

It is also responsible for data flow between memory and other components. So, if it is causing CPU spike, you need to check carefully as it is an essential process and cannot be put to sleep, closed or ignored in anyway.


Find out your system’s motherboard’s manufacturer and its exact model. Now go to its manufacturer’s website and choose latest BIOS update for your motherboard’s model.

Download updated BIOS driver and install it. Additionally, go through manufacturer’s instructions properly before installing it.

If you do not understand any detail, do not proceed with installation as it might damage your computer.

Go through various sources, instruction manuals, guides and tutorials to understand BIOS driver’s complete installation process properly and even then, proceed with caution.

If you are unable to figure out how to install updated BIOS, or simply do not have time for it, you must contact an expert for technical assistance or have them do it for you.


If you are attempting to play a CPU resource-intensive game on a low-end CPU this guide might not be able to help you much.

However, if you have a fairly new PC which keeps experiencing sudden and random CPU spikes you need to rectify its errors by going through the aforementioned reasons and solutions for why does CPU usage spikes to 100.