The fastest fixes work on what's already slowing you down
A slow computer usually isn't slow everywhere at once. It's slow at startup, or when you open your browser, or when you switch between programs. Finding which one is the culprit — and fixing it — takes 20 minutes and costs nothing.
The most common causes are a full hard drive, too many programs running at startup, browser extensions you forgot about, and malware or bloatware that came with your system. Each one has a specific fix. You don't need to buy more RAM or a new drive unless you've already tried these steps and your computer is still dragging.
Key Takeaways
- Restart your computer first — it clears temporary files and stops programs that are stuck in memory, and solves slowness about 30 percent of the time.
- Check your hard drive space in Settings or System Preferences; if you have less than 10 percent free, delete old files, empty your Recycle Bin or Trash, and uninstall programs you don't use.
- Disable startup programs in Task Manager (Windows) or System Preferences (Mac) so they don't load when you turn on your computer.
- Remove browser extensions you don't recognize or use, because each one runs in the background and consumes memory and processing power.
- Run a malware scan with Windows Defender (Windows) or Malwarebytes to catch unwanted software that slows your system without your knowledge.
Clear space on your hard drive
When your hard drive is nearly full, your computer has nowhere to write temporary files, and everything slows down. Windows and Mac both need at least 10 percent of your drive free to run smoothly.
On Windows, open Settings, select System, then Storage. You'll see how much space you're using and what's taking it up. Large video files, old downloads, and backup folders are usually the culprits. Delete what you don't need, then empty the Recycle Bin. On Mac, open System Preferences, click General, then Storage, and follow the same process — delete old files and empty the Trash.
If you're close to full and don't want to delete anything, move large files to an external drive or cloud storage like Google Drive or OneDrive. This frees up space without losing the files.
Stop programs from running at startup
Every program you install asks to run when your computer starts. If you've installed 20 programs over two years, your computer is now loading 20 things before you even open a browser. This is why startup takes five minutes instead of 30 seconds.
On Windows, press Ctrl+Shift+Esc to open Task Manager, click the Startup tab, and you'll see every program that runs at boot. Right-click anything you don't need running in the background — Spotify, Slack, Adobe updates, printer software — and select Disable. You can still open these programs manually whenever you want; they just won't load automatically.
On Mac, open System Preferences, click General, then Login Items. You'll see a list of programs that open at startup. Select each one you don't need and click the minus button to remove it.
Remove browser extensions and clear cache
Browser extensions are small programs that run inside your web browser. Each one uses memory and can slow down page loading. If you have 15 extensions and only use 3, you're wasting resources.
In Chrome, click the three-dot menu, select More Tools, then Extensions. Look through the list and remove anything you don't recognize or haven't used in months. Do the same in Firefox (click the menu, select Add-ons, then Extensions) or Edge (click the three-dot menu, select Extensions).
While you're there, clear your browser cache — the temporary files your browser stores to load websites faster. In Chrome, press Ctrl+Shift+Delete (Windows) or Command+Shift+Delete (Mac), select All Time, and click Clear Data. A full cache can slow down your browser noticeably, especially if you've been using the same browser for years.
Check for malware and unwanted software
Malware and bloatware — programs installed without your permission or bundled with software you wanted — can run constantly in the background and consume CPU and memory. Windows Defender comes built into Windows and runs automatically, but you can also run a manual scan.
On Windows, open Windows Security (search for it in the Start menu), click Virus & Threat Protection, then click Scan Options. Select Full Scan and click Scan Now. This takes 20 to 60 minutes depending on your drive size, but it will catch most malware.
For a second opinion, read Malwarebytes (the free version is sufficient) and run a scan. It catches things Windows Defender sometimes misses. On Mac, malware is less common, but you can still read Malwarebytes and run a scan if your computer is unusually slow.
Disable visual effects and animations
Windows and Mac both use animations and visual effects — shadows, transparency, fade-in effects — that look nice but consume processing power. On older computers or those with slower processors, turning these off can make a noticeable difference.
On Windows, open Settings, select System, then About. Click Advanced System Settings on the right, then click the Advanced tab. Under Performance, click Settings. Select Adjust for Best Performance to turn off all animations, or select Custom and uncheck only the effects you don't care about (like fade effects or window animations).
On Mac, open System Preferences, click Accessibility, then Display. Check Reduce Motion to disable animations. This is a smaller change on Mac than on Windows, but it still helps on older machines.
Upgrade your RAM or switch to an SSD if nothing else works
If you've done all of the above and your computer is still slow, the problem is likely hardware. RAM (memory) and storage speed matter. If you have 4 GB of RAM and you regularly open 20 browser tabs plus Photoshop, your computer will struggle no matter how clean it is.
Adding RAM is cheap and straightforward on most laptops and desktops — you can buy 8 GB or 16 GB for $30 to $80 and install it yourself in five minutes. Check your computer's manual or search "[your computer model] RAM upgrade" to see if it's user-replaceable.
A bigger upgrade is replacing your hard drive with an SSD (solid-state drive). SSDs are 10 times faster than traditional hard drives and make everything feel snappier — startup, opening programs, loading files. A 500 GB SSD costs $40 to $60. If your computer is more than five years old and still has a traditional hard drive, this upgrade alone will make it feel like a new machine.
Frequently Asked Questions
How long should I wait after restarting before I judge if my computer is faster?
Wait at least five minutes. Your computer is still loading programs and indexing files during startup. Open the programs you use most and see if they load faster than before. Real improvement usually shows up in the first week as Windows or Mac finishes background maintenance tasks.
Is it safe to disable all startup programs?
Yes. Disabling a startup program doesn't uninstall it — you can still open it manually whenever you want. The only exception is security software like antivirus; if you have third-party antivirus installed, leave it enabled. Windows Defender is fine to disable if you prefer another antivirus.
What's the difference between clearing cache and clearing browsing history?
Cache is temporary files your browser stores to load websites faster next time. History is the list of websites you've visited. Clearing cache frees up space and can speed up your browser; clearing history just removes the list. You can clear one without the other.
How much free space do I actually need on my hard drive?
At least 10 percent of your total drive size. If you have a 500 GB drive, keep at least 50 GB free. If you have a 1 TB drive, keep at least 100 GB free. Below that, your computer will slow down noticeably because it has nowhere to write temporary files.
Can I undo changes I made in Task Manager or System Preferences?
Yes. If you disabled a startup program and now you want it back, open Task Manager or System Preferences again and re-enable it. Nothing is permanent — you're just changing settings, not deleting anything.