Why your PC is so slow... and how you can speed it up

Struggling with a slow computer? Find out why your PC is so slow and discover a few ways to speed it up

A slow computer can make even the simplest of jobs feel like a real hassle. Luckily, there are plenty of things you can do to speed up your PC and improve its performance.

Read on to discover how to fix a slow computer and prevent your machine from slowing down further in the longterm.

Why is my computer slow?

Your operating system has to manage the resources of your computer (memory, drive space, processing power) between all the programs that are running on it. There’s a huge number of things that may be reducing your computer’s performance, but they usually boil down to your PC’s resources being used inefficiently.

Here are some of the things that slow down your computer:

  • Running out of RAM (Random Access Memory)
  • Running out of disk drive space (HDD or SSD)
  • Old or fragmented hard drive Too many background programs
  • Too many start-up programs
  • Falling behind on Windows or driver updates
  • Malware or viruses
  • Special effects and visual features

If your computer is running slow, read on for ways to fix each of these issues.

How to make your computer faster

Restart your computer

If your computer speed is not what it should be, the first thing to try is restarting your computer.

Your operating system allocates space in RAM for programs as they run on your computer. Your RAM will eventually fill up, which will slow down your computer as your operating system starts using the swap file instead.

The swap file is a file on your disk drive that your operating system uses for data that is currently being used by programs, when your RAM, which is normally used for that purpose, runs out of space. Since hard drives and even the much faster SSD’s are slower than RAM, your computer will slow down significantly when it resorts to using the swap file.

Simply closing programs that are running on your computer helps, but restarting your computer allows it to be refreshed in a number of other ways as well. It ensures programs won’t keep running on the background (scroll down for more about background programs), allows Windows updates to be installed, and can fix a number of bugs that you might be suffering from, such as memory leaks, which cause programs to eat up much more RAM than they should.

If you notice applications starting up automatically after you have restarted your computer, your PC performance might be suffering from start-up programs. Scroll down to the start-up program section of this guide to learn more about them and how you can stop them from slowing down your computer.

Clean your hard drive

When your hard drive memory is full, it slows down your computer because the operating system doesn’t have enough free space to work adequately. Your OS needs space to use the swap file, prevent fragmentation, and to create temporary files (more on these later).

To make sure that your computer isn’t slow because of a full hard drive, ensure that there is at least 500MB (megabytes) of disk space available. You can check how much free space you have by opening File Explorer and clicking ‘This PC’ on the left navigation bar. Your main drive will normally be called ‘Windows (C:)’, but if you have other drives you can also see how much space they have from this screen.

Even if you have multiple drives it’s best to make sure that each individual drive has a buffer of 500MB to help the operating system manage the files on the drive better.

Here are some tips for doing a disk cleanup and increasing the performance of your PC:

  • Empty your Recycle Bin. Files build up in the recycle bin when you use your PC, so clearing it occasionally will help you keep up the performance of your computer. Double-click the Recycle Bin icon on your desktop, right click anywhere and select ‘Empty Recycle Bin’. You can also right-click on the Recycle Bin icon itself.
  • Remove unwanted programs. Programs that you don’t want or need may be taking up hard drive space and slowing down your PC. To remove them, open Control Panel through the Windows search bar (accessible via the Windows icon in the bottom-left of your screen) and click ‘Uninstall a program’ under the Programs header. Use the window that opens up to uninstall programs that you don’t need.

Any third-party programs like bundled games and camera apps will normally be safe to remove. But if something has Microsoft or ‘driver’ in the name it might be a good idea to Google the program and check what it does before removing it, so you won’t accidentally remove something that your operating system needs to function.

  • Clean your Downloads folder. Open File Explorer and select Downloads from the Quick Access bar to the left. Move the files that you still need to the appropriate folders, such as Documents, and simply delete the rest. If you don’t regularly clean this folder, the files you download from the internet will accumulate, taking up space on your hard drive and slowing down your PC.
  • Find and delete temporary files. These are files that programs and your operating system use to store temporary data, such as files that programs download when installing updates. Over time temp files can build up to take a lot of space on your hard drive. Temporary files can be quite tricky to find as they are mostly in hidden folders, and it’s hard to know what is safe to remove. You can access your main temporary file folder by exiting all open programs, pressing the Windows key + R, typing in %TMP% and clicking ‘OK.’ This will bring up a folder that contains most of the temporary files on your computer, however it may include files that programs are still using and shouldn’t be removed.

 

To safely remove temporary files that your computer doesn’t need anymore, it’s best to use a program like CCleaner, which can do it for you in one click.

  • Clear the cache and cookies on your web browser. The cache (webpages your browser saves to improve browsing speed) and cookies (data stored on your computer by websites you visit) build up as you browse the web, and unless you clear them regularly they can take up a large amount of space on your drive. Most browsers have the option to clear these somewhere in their settings menu. For more about cookies and the cache and instructions on how to clear them on each browser, head over to our articles ‘How to clear your browser cookies’ and ‘What is my cache and why does it need clearing.’

How to clear cookies from your browser

If you’re still struggling to make space on your hard drive, consider storing your files and documents in the cloud to free up space on your own drive. Services like Google Drive, Dropbox, and OneDrive all provide a couple of GB (gigabytes) of free storage, with the option to upgrade up to TB (terabytes) of storage for a monthly fee. These services allow you to not only clear your hard drive of data and improve your computer’s performance, but also give you the ability to access your files from any computer or phone with an internet connection.

You can also use CCleaner to clear up your Recycle Bin, Downloads folder, temporary files and your browser cache and cookies in one go, quickly freeing up space on your hard drive and improving the performance of your PC.

Defragment your hard drive

When you free up space on your hard drive, it doesn’t go into a big pot of free space, it remains where the deleted data was filed as a fragment. After a while, your hard drive fills up and starts to use up the little free fragments - creating your document or file from a number of locations on the disc. This takes more time for your computer to do.

Defragmenting – or defragging - your hard drive organizes the disorganized bits of data on your hard drive into easily accessible and ordered blocks. If your PC has slowed down over time, defragmenting can help speed it up. In particular, programs that have large file sizes (video editors, games, etc) will cause your hard drive to fragment and defragmenting will improve their performance. To read more about the benefits of defragging and how you can do it on your PC, head over to our article ‘How to defrag your computer.’ You can also use software such as CCleaner’s Defraggler to easily defragment your computer.

Disable background programs

A slow computer is often caused by too many programs running simultaneously, taking up processing power and reducing the PC’s performance. Some programs will continue running in the background even after you have closed them or will start automatically when you boot up your computer.

To see what background programs are running on your PC and how much of your memory and processing power they


are taking, open Task Manager, which you can access by pressing CTRL+ALT+DELETE.

On Windows, 10 Task manager may open in a simplified view, in which case you’ll need to click ‘More details’ at the bottom first.

Click the CPU, Memory, and Disk headers to sort the programs that are running on your computer by how much of your computer’s resources they are taking. For example, if your memory bar is close to or at 100%, you should sort programs by their memory use and close the ones that you don’t need.

It’s possible to close programs directly from the Task Manager by selecting them and clicking ‘End task’ at the bottom right. However, if you don’t know what a program does, you should Google it first to check so you don’t accidentally close something that your operating system needs.

Disable start-up programs

If your computer has slowed down and the time it takes to boot has gone up, it is likely because there are too many programs running on start-up. Lots of programs come with an option to run automatically at boot. This is useful if you’re going to use the program whenever you’re on your computer, but if there are too many programs that run on start-up it can seriously slow down your boot time as well as reduce your performance when they run in the background.

On Windows 8 and Windows 10, you no longer need to use the System Configuration tool to manage start-up programs as you did in Windows 7. Instead, you can do it right from the Task Manager, which you can open by

pressing CTRL+ALT+DELETE and clicking ‘Task Manager’. Click on the ‘Start-up’ tab at the top to see what start-up programs are enabled and their impact on your computer’s boot time and performance.

To disable a program from starting up automatically, select it and click ‘Disable’ in the bottom-right corner. Make sure to not disable programs you actually need, like your antivirus or driver programs.

You can also easily and safely manage start-up programs on any computer with CCleaner. The options to manage start-up programs in CCleaner can be found in Tools > Start up, where you can simply click Disable on the programs you don’t need starting up with your PC.

Scan for malware and viruses

Malware and viruses will slow down your computer if it has been infected. Make sure that you are using an up-to-date antivirus program, and run any scans to find viruses that may be eating up your computer’s performance.

Upgrade your memory

Random Access Memory is what your computer uses to store information that the operating system and programs running on it are currently using - unlike your disk drives (HDD or SSD) which are where programs and files are otherwise stored. A memory upgrade is one of the best ways to increase computer speed and performance.

If your computer has less than 4GB of RAM it will likely be slowed down when programs have to compete for their share of memory. When RAM runs out, your computer starts using a file on the hard drive called the swap file instead – and as hard drives are much slower than RAM, you’ll notice a significant difference in performance.

If you use programs that need to store a large amount of information in memory for quick access, such as games and video-editing programs, you should have at least 6GB of RAM so your computer won’t have to resort to using the swap file too often.

If you have a desktop computer upgrading your RAM should be relatively easy, you will just need to purchase your new RAM and stick it into the slots that will be pointed out to you in your motherboard’s manual. On laptops, upgrading your RAM may or may not be possible without purchasing an entirely new computer. You will have to refer to your laptop’s manual to see if upgrading your RAM is possible on your own device.

Upgrade your hard drive

If your computer is slow when booting up, opening files or loading games, you will see a great increase in performance by switching from a hard drive to a solid-state drive. Unlike hard drives where the drive spins around to allow data to be read from it, SSD’s do not have any moving parts, instead of storing data on interconnected transistors that work at lightning speed. When hard drives start up it takes time for the drive to spin to full speed, whereas SSD’s work instantly, allowing data to be read much faster and speeding up your PC.


If you have a desktop PC, buying and installing an SSD should be easy, and you can find plenty of guides on finding and installing the right SSD online. If you have a laptop, however, changing your disk drive will likely prove hard or impossible. Lots of new laptops do have SSD’s so it’s something you can keep in mind for when you decide it’s time to upgrade your laptop.

Install system updates

Making sure that your computer has the latest Windows updates, as well as having up-to-date drivers, is important for the best PC performance. New Windows and driver updates provide performance improvements, and falling behind on them may cause your PC to slow down. You can manage your computer’s updates from the Settings menu.

  • Open the Windows start menu, and click the Settings icon on the left.
  • Click Update & Security.
  • This page will tell you if you’re behind on Windows updates, and what steps you need to take if you are. 

Reinstall Windows

If all else fails, reinstalling Windows is the best option to try before resorting to new hardware. If you have used your computer for a while chances are that you’ve built up programs and files that you don’t use anymore. And while cleaning them out one by one helps, only by uninstalling then reinstalling Windows can you be sure that you’ve gotten rid of everything. All your settings and drivers will be reset to default.

Remember to backup all your important files before reinstalling Windows, as this process will clear all data from your hard drive. You can use Windows’ own backup tool which you can find by searching ‘backup’ in the start menu, or you can save your files on the cloud services discussed earlier.

Additional speed issues with Windows 10

Windows 10 added some special effects and visual features like animations and shadows which take up processing power. Disabling them may improve your Windows 10 performance.

  • Type in ‘Performance’ in the Windows search bar and select ‘Adjust the appearance and performance of Windows.’
  • On the Visual Effects tab, click ‘Adjust for best performance’ and then ‘Apply.’ This will disable all unnecessary visual features and stop them from slowing down your Windows 10 PC.

Windows 10 installations will often come with defaults apps, which can be uninstalled to free up disk space and improve performance if you don’t use or need them. Some of these you can uninstall like any other program (see above), but others annoyingly won’t give you the option to be uninstalled directly.

We hope that helps!

If you have any comments, please tweet us. We're @Piriform.


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