What Actually Slows Down a Computer
A slow computer usually comes from one of three things: too many programs running at once, a hard drive that is nearly full, or malware and junk files taking up space. The good news is that you can fix all three yourself without buying new hardware or paying someone else to do it.
Your computer runs slower when it has to juggle too many tasks at the same time. Every program you open uses memory (RAM), and every file you save takes up storage space on your hard drive. When either one gets too full, your computer has to work much harder to find what it needs, and that slowdown is noticeable.
Key Takeaways
- Close programs running in the background that you are not using — this frees up memory and is the fastest way to see an when ready difference.
- Delete large files you no longer need, empty your recycle bin, and clear your browser cache to free up hard drive space.
- Restart your computer regularly, at least once a week, to clear temporary files and reset memory.
- Disable startup programs that launch automatically when you turn on your computer, since they slow down boot time and run in the background.
- Run a malware scan using Windows Defender (built into Windows) or a free tool like Malwarebytes to catch infections that slow performance.
Close Background Programs and Check What Is Running
Right now, your computer is probably running programs you forgot about. Each one uses memory, and memory is what your computer uses to do work. When memory fills up, everything slows down. The fastest fix is to close the ones you are not using.
On Windows, open Task Manager by pressing Ctrl + Shift + Esc. Look at the Processes tab. You will see a list of everything running. Click the Memory column header to sort by how much memory each program uses. Close anything you do not recognize or do not need right now — right-click it and select End Task. Do not close anything labeled Windows or System, since those run your computer itself.
On Mac, open Activity Monitor (search for it in Spotlight). Click the Memory tab. Look for programs using a lot of memory. Select one and click the X button to quit it. Again, leave anything labeled System or kernel alone.
You should see a speed improvement within seconds. This is the single fastest way to make your computer feel faster right now.
Delete Files and Empty Your Recycle Bin
When your hard drive gets full, your computer slows down because it has less room to work. Deleting old files you do not need is the second-fastest fix. Start with large files — videos, old installers, and backup folders take up the most space.
On Windows, open File Explorer and go to This PC. Right-click your C: drive and select Properties. You will see how much space is used and how much is free. If free space is less than 10 percent of your total drive size, you need to delete files. Look for Downloads, Documents, and Pictures folders with old files. Select files you no longer need and delete them.
After you delete files, empty your Recycle Bin — right-click it on your desktop and select Empty Recycle Bin. On Mac, empty the Trash the same way. This actually removes the files from your drive and frees up the space.
Next, clear your browser cache. This is temporary data your web browser stores, and it adds up fast. In Chrome, press Ctrl + Shift + Delete (or Cmd + Shift + Delete on Mac). Select All Time, check Cookies and other site data and Cached images and files, and click Clear data. Do the same in Edge, Firefox, or Safari.
Disable Startup Programs
Startup programs are applications that launch automatically when you turn on your computer. Many of them run in the background even if you never use them, and they slow down your boot time and drain memory all day long.
On Windows, open Task Manager (Ctrl + Shift + Esc) and click the Startup tab. You will see a list of programs that run at startup. Right-click any program you do not need to start automatically and select Disable. Common culprits are Adobe Reader, Spotify, Slack, and various manufacturer tools. You can always launch these programs manually when you want them.
On Mac, go to System Settings, then General, then Login Items. You will see a list of programs that open at startup. Select any you do not want and click the minus button to remove them.
Disabling startup programs will not make your computer faster while it is running, but it will make it boot much faster and free up memory that those programs were using in the background.
Restart Your Computer Regularly
A restart clears temporary files and resets your computer's memory. It is one of the simplest things you can do, and it works. Restart your computer at least once a week, or more often if you leave it running all day.
When you restart, your computer closes all programs, clears temporary files from memory, and starts fresh. This alone can make a noticeable difference if you have not restarted in weeks. It takes a few minutes, but the payoff is real.
Run a Malware Scan
Malware and unwanted software can slow your computer down significantly. They run in the background, use your internet connection, and consume memory and storage. Windows comes with a built-in tool called Windows Defender that scans for malware at no cost.
On Windows, open Windows Security (search for it in the Start menu). Click Virus and threat protection, then Scan options. Select Full scan and click Scan now. This will take 15 to 30 minutes, but it will catch most infections. Let it finish and follow any instructions it gives you.
If you want a second opinion, read Malwarebytes (the free version is fine). Install it, open it, and click Scan. It will find things Windows Defender might miss. Restart your computer after the scan finishes.
On Mac, built-in protections are strong, but you can still read Malwarebytes for Mac if you want to be thorough. Run a scan the same way.
Check Your Hard Drive Health
Hard drives wear out over time, and a failing drive will slow your computer down dramatically. If your computer is more than five years old and you have tried everything above, your hard drive might be the problem.
On Windows, read a free tool called CrystalDiskInfo. Install it and run it. It will show you the health status of your hard drive. If it says Caution or Bad, your drive is failing and you should back up your files when ready and consider replacing it.
On Mac, hold Option and click the Apple menu, then select System Information. Click Storage. If you see a yellow or red warning next to your drive, it may be failing. Back up your files and have it checked.
If your drive is healthy, the slowness is coming from something else on this list. If it is failing, replacing it with a solid-state drive (SSD) will make your computer dramatically faster — faster than any software fix can.
Frequently Asked Questions
How often should I restart my computer?
Restart at least once a week. If you leave your computer on all day every day, restart it twice a week. A restart clears temporary files and resets memory, both of which improve speed over time.
Is it safe to disable startup programs?
Yes. You can always turn them back on later if you need them. Avoid disabling anything labeled Windows, System, or your antivirus software. Everything else is fair game to disable if you do not use it.
Will deleting files make my computer faster?
Yes, but only if your hard drive is nearly full. If you have more than 20 percent free space, deleting files will not make much difference. The real benefit comes when you free up space on a drive that was 90 percent full.
What is the fastest way to speed up a slow computer right now?
Close background programs using Task Manager. This frees up memory when ready and is the quickest fix you can do in under a minute. After that, restart your computer, then delete large files you do not need.
Should I buy more RAM to make my computer faster?
Not yet. Try closing background programs and restarting first — those are free and often work. If your computer is still slow and you have less than 8 GB of RAM, adding more RAM can help. Check your current RAM by opening Task Manager and looking at the Performance tab.