CPU Usage Super High (Or At 100) Even When Barely Anything Is Running? 16 Proven Fixes

A slow computer is one of the most annoying IT issues you can have, especially because they can be so difficult to debug. Finding the issue and resolving can be difficult.

This video covers 16 different things you should check and change to speed up your computer and hopefully start getting lower CPU usage.

I cover everything from Windows power modes and visual effects, to viruses… and slow anti-virus programs!

I also dive into some more physical things you can try, like cleaning out your PC’s vents/fans, and potentially replacing the thermal paste (TIM) on your CPU.

The 16 fixes I cover are:

  1. Power Modes
  2. Background Apps
  3. Start-up Apps
  4. Is this happening in just a single program?
  5. Viruses
  6. Anti-Virus Programs
  7. HPET
  8. Windows Updates
  9. Close down unused programs
  10. Windows Visual Effects
  11. Reduce Game Graphical Settings
  12. Clean out your PC
  13. Fans And TIM
  14. Overclock Your CPU
  15. Reinstall Windows
  16. Exchange or upgrade your PC

If you prefer text over video, please read on for the guide/transcript version of this video.

Video Transcript And Guide

Hey everyone, if your computer is running REALLY slow, you might have checked Task Manager and spotted that CPU usage is really high – or even that it’s maxed out at 100%. Some ‘tutorials’ online tell you to do random things like set the number of boot CPU cores to 8 or whatever, but this has no impact on system performance.

Setting the boot cores in msconfig
Setting the boot cores in msconfig

So I wanted to shoot this video and discuss actual, USEFUL things you should do to reduce CPU usage.

Before we start though, you should create a system restore point because we’ll be modifying various Windows settings and it’s always a good plan to create a ‘backup point’ that you can come back to, just in-case something goes awry. To do this, hit the Windows key and search for “restore point”. Select the “Create a restore point” option, and then click “Create” in the window that appears. Enter a name and click okay. Windows should take less than a minute and confirm that a restore point was created.

Power Modes

Now we can start speeding up your PC. The first thing to check is your Windows power mode settings, especially if you have a laptop (because laptops tend to have various power saving settings that can slow down your system a lot). Hit the Windows key and search for “Control Panel”. Then search for Power and select “Choose a power plan“. From here, select an option like “High performance” or “Ultimate performance”.

Changing the power plan on Windows
Changing the power plan on Windows

This will allow your CPU to run to its full potential, and not be artificially held back to save battery life. Next click “Change plan settings” and go to advanced settings. Expand out Processor Power Management and ensure that the maximum state is set to 100%. Anything less will again hold back your CPU, which is not ideal.

Background Apps

That previous step can help a lot, especially on a laptop, but the second thing to check is what “background apps” are running. Windows 10 and 11 have quite a lot of bloat behind the scenes, including running various apps that you don’t really need. To check these, search for “Settings” then click into Apps then Installed Apps.

Various background apps on Windows
Various background apps on Windows

If you don’t recognize – or use – some of these apps, click the three dots on the right and if they have an “Advanced Options” setting, click this and scroll down to the Background apps section. In the dropdown, choose “Never” and this will effectively stop this program from running next time you restart your PC. Unfortunately it does take quite a long time to go through all the bloat that Windows installs by default, but this step can be useful – especially if, for example, you never use the Xbox gaming features on Windows (it’s worth turning that off if so).

Start-up Apps

The third thing to do is review your start-up apps. These are the programs that start up automatically when your PC first boots up. Sometimes programs insert themselves into this list, even if you barely ever use them. These programs then constantly run, draining your CPU. So, from the same window, click “Apps” to go back, and then go to “Startup” (although you can also access this feature from Task Manager).

Various start up apps on Windows
Various start up apps on Windows

Check through this list and disable anything you don’t want, for example I’ll disable “GOG Galaxy” here because there’s no reason for this to automatically run every time I turn my PC on.

Just A Single Program?

The fourth thing to check when you have high CPU usage is whether ALL your programs are slow, or just a single one. I remember when I first tried doing video editing on my old PC, Davinci Resolve was really, really laggy. I’m not sure why this happened, because Davinci is a quality bit of software, but it just seemed to hate my old PC. If just a single program is slow for you, try and see if there are any updates for that program – maybe you just have an older, buggier version. Also try Googling around a bit and seeing if there are some settings to change that will make the program run faster. If all else fails, try and see if there is an alternative program to use – just like how I ended up using Premiere Pro instead of Davinci.

Viruses

The fifth reason why your PC can be slow is if it has a virus (or malware). Unless your PC is brand new and has always been slow, a virus is a likely cause for a slow PC. There was a time when everyone seemed to run proper anti-virus programs, but nowadays many people just rely on Windows Defender which can be okay, but it’s not perfect. I would download something like Avast, Kaspersky or Bitdefender (if you haven’t already), and run through a full scan.

Screenshot of the Bitdefender download page
Screenshot of the Bitdefender download page

This might take some time, but it will be worth it to either catch – or rule out – any suspicious programs that might be running on your PC.

Anti-Viruses!

Ironically, though, the sixth reason why your PC might have high CPU usage is that anti-virus programs SUCK. Yes I know that I bigged up their benefits on the last point. It IS worth having an anti-virus program installed, but you should only have ONE installed. Don’t try and mix and match them – it can be a bit like mixing bleach and chlorine… they don’t work well together. Equally some anti-virus programs like Trend Micro and Norton can slow down your PC a LOT, especially when running a full scan. You could try temporarily exiting your anti-virus (and ignoring the warnings that appear) and see whether your PC is now faster. If it is, download something like Avast because that’s one of the fastest virus checkers:

Running a virus scan in Avast
Running a virus scan in Avast

HPET

The seventh thing to try can be especially important if you’re having really slow performance when gaming. Windows has something called HPET and this can sometimes slow everything down, so it’s worth disabling it and seeing if that helps. To do this, hit the Windows key, search for “Device Manager” and open this. Expand out “System Devices” and scroll down to High Precision Event Timer.

HPET listed in Windows Device Manager
HPET listed in Windows Device Manager

Right click this and disable it. Restart your PC and see whether the performance issues go away: many gaming benchmarks show a clear improvement in FPS after disabling HPET.

Windows Updates

Number eight is to check for pending Windows updates. Search for “updates” and click through to Windows Update, and trigger a manual check for pending updates if it doesn’t do this automatically. While installing updates CAN actually slow down your PC (ironically), your system slowness might be due to a genuine bug in Windows or a driver, so getting everything updated can help a lot (once it’s all installed).

Close Unused Programs

Now at this point it’s worth diving into Task Manager, because for the ninth fix you should close down any programs that are using a lot of CPU usage that you don’t actually use. Right click the bottom of the screen and click Task Manager, then in the sidebar go to Processes and click “Show more” if you’re on an older operating system. This will list all programs and background apps that are running. You can then right click on a program and stop it – which can speed up your PC – but you should only do this if you know for sure what the program is.

Ending a task in Windows Task Manager
Ending a task in Windows Task Manager

For example, killing “Windows Start-up Application” is NOT good, because ending this progress could crash your PC.  However if a program you installed is running and using lots of CPU, then ending this process could be a good idea.

Visual Effects

My tenth fix involves reducing some of the fancy visual effects that Windows 10 and 11 introduced, because these can cause some PCs to be laggy. To get started, click Settings then Accessibility. Click into Visual Effects on the right, and then disable both “Transparency effects” and “Animation effects”.

Transparency and visual effects in Windows
Transparency and visual effects in Windows

Use your PC for a few minutes after this, and see if it’s any quicker. Of course, it won’t look as “flashy” anymore so if this tip DOES help, you might want to re-enable 1 or 2 specific visual effects that you like and check whether they impact performance. This will improve some trial and error, but I’ll put details in the description about how to do this.

Reduce Game Graphics

Next up, number 11, if your CPU usage is too high mainly when gaming, it might be that your PC’s hardware is just a bit too slow to fully play that game – at the current graphical settings. Thankfully pretty much every game allows you to go into the settings and reduce the graphical quality, and maybe the resolution too.

Various game resolutions in Sniper Elite 5
Various game resolutions in Sniper Elite 5

For example playing a game at 1080p not 1440p will be easier for your PC to handle, meaning that your games will also be faster. Also reducing or disabling effects like “anti-aliasing” and motion blur can really help to improve performance and speed things up, but naturally this will make your game look a bit less smooth so you don’t want to reduce things too far.

Clean Your PC

Number 12 involves getting physical… with your PC. Laptops and PCs will have little vents that allow fresh air in and out, but if these are clogged with dust, your PC’s thermals will be higher and this can impact performance. So clean out any dust by gently using a flat vacuum cleaner end that doesn’t insert anything into the PC itself.

A flat vacuum cleaner end is best when cleaning the outside of your PC case
A flat vacuum cleaner end is best when cleaning the outside of your PC case

Also consider opening up the case if you have the skill to do this, and clean out any dust gently using something like compressed air. This will literally blow away the dust, and can work really well.

Fans And TIM

Following on from this, number 13 applies more to desktop PCs. A well designed computer will have a number of case fans – some will take in new air, and some will expel that air out the case. If your case has some empty slots where a case fan could be, then your poor performance might be down to insufficient cooling – so consider buying new case fans and hooking them up, or taking your PC to a repair shop. Equally if your computer is 7 or 8 years old, you might need to replace the TIM on the CPU.

Thermal paste TIM put onto the AMD Ryzen CPU
Thermal paste TIM put onto the AMD Ryzen CPU

This isn’t a simple job because you have to remove the CPU cooler and clean out the old TIM, but I’ll drop some links in the description that show how to do this if you’re experienced enough to attempt this. Getting new TIM and improving your case fans configuration can REALLY help to cool your PC, driving up system performance.

Overclock CPU

Number 14. If your PC is STILL quite slow, and your CPU is a little bit outdated – or just struggling with some new programs or games – you might want to consider overclocking it. This is where you tell your CPU to run faster than its original “instructions”, possibly by sending more power to it – so this can be a bit of a minefield, and you should only do this if you know what you’re doing. But it can make your CPU run a few percent quicker, which is a nice free boost. Some PCs and laptops come with overclocking software such as within Intel XTU or AMD Ryzen Master, although programs like ParkControl and CPU Tweaker also help out here.

Auto overclock mode in AMD Ryzen Master
Auto overclock mode in AMD Ryzen Master

The exact process for overclocking will vary depending on your CPU and the software you’re using, but you’ll usually want to increase the frequency (speed) that your CPU runs at. If your PC crashes, you’ll want to increase the voltage that is supplied to your CPU – or drop the frequency back a bit. This method involves a lot of trial and error but it can help for sure.

Reinstall Windows

My fifteenth tip is to consider reinstalling Windows if your PC is still slow. A decade ago, reinstalling an OS took AGES – requiring lots of different install DVDs to get all the programs and drivers back. But nowadays you often just need to boot back into the original install media (like the boot USB), follow the reinstall instructions, and then when you’re back up and running, Windows will automatically install the majority of the drivers.

Two exactly the same NVMe SSD showing up in Windows during the first installation
Reinstalling Windows onto a new drive.

You’ll then just need to re-download the programs you tend to use the most, for example Microsoft Word, Steam for games or a browser like Chrome or Firefox. The benefit of a full reinstall is that you’re starting fresh and any weird background programs – or even viruses – that were draining your CPU will be washed away.

Exchange Or Upgrade PC

However my last “fix”, if your computer is still way too slow, is that you might just need to upgrade or exchange your PC. Maybe you purchased a refurbished system and it still has faults, in which case you should look to refund or exchange it. But if you’ve had your PC for many years, it might be time to either upgrade various components (like the CPU and RAM) OR buy a new computer entirely.

Various power cables have been installed in my build but there is no cable management yet
Various power cables have been installed in my build (there was no cable management at this point – I did this later on)

Sometimes software moves on and requires faster and faster computer systems, so unfortunately an upgrade can sometimes be needed.

cropped A picture of me Tristan
About Tristan Perry

Tristan has been interested in computer hardware and software since he was 10 years old. He has built loads of computers over the years, along with installing, modifying and writing software (he's a backend software developer 'by trade').

Tristan also has an academic background in technology (in Math and Computer Science), so he enjoys drilling into the deeper aspects of technology.

Tristan is also an avid PC gamer, with FFX and Rocket League being his favorite games.

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