Speed Up a Slow Computer
A slow computer almost always has a specific cause: one app hogging everything, too much starting up, a full drive, or aging hardware. This guide helps you find which one, then fix it.
What kind of slow is it?
- Suddenly slow today: usually a background update, virus scan, sync or a stuck app. Steps 1–2 fix most of these.
- Slow to start up: too many apps launching at login. Step 3.
- Slow in the browser only: tabs and extensions. Step 4.
- Gradually slower for months or years: storage, updates or hardware. Steps 5–8.
FIXTry these in order
Open a step, try it, then tell us if it helped.
Computers that go weeks without a restart pile up stuck processes and memory leaks. A restart clears them all.
Use Start › Power › Restart, not Shut down. With Windows' Fast Startup feature, “Shut down” saves part of the system to disk and reloads it, so problems can survive it. Restart starts completely fresh.
Choose Apple menu › Restart, and untick Reopen windows when logging back in so you don't bring the clutter back with you.
Press Ctrl Shift Esc to open Task Manager. On the Processes page, click the CPU, Memory and Disk column headers to sort by each.
If one app is near the top using a lot, and you don't need it right now, select it and click End task.
Press ⌘ Space, type Activity Monitor and open it. Click the % CPU column on the CPU tab, then check the Memory tab, where a yellow or red Memory Pressure graph means you're short on memory.
To close a runaway app, select it and click the × button in the toolbar, then Quit.
In Task Manager, open Startup apps. Look at the Startup impact column and Disable anything you don't need the moment you sign in, like game launchers, chat apps and updaters. Disabling doesn't uninstall them; you can still open them yourself.
Go to System Settings › General › Login Items. Select apps under Open at Login you don't need right away and click –. Also review the Allow in the Background list.
Keep your antivirus, cloud backup and anything from your computer's maker for audio, touchpad or graphics.
Every open tab uses memory, and some sites (video, email, social media) use a lot even in the background.
- Close tabs you aren't using. Bookmark them if you want them later.
- Remove browser extensions you don't recognise or use. In Chrome or Edge, type
chrome://extensionsoredge://extensionsin the address bar. - Turn on tab sleeping: Memory Saver in Chrome's Settings › Performance, or Sleeping tabs in Edge's Settings › System and performance.
When the main drive is nearly full, the system has no room for the temporary files it needs while working, and everything slows down. Aim to keep at least 15% free.
Our Free Up Disk Space guide walks through it step by step.
Install everything in Settings › Windows Update, including optional driver updates, then restart.
Laptops: check Settings › System › Power & battery › Power mode. Best power efficiency deliberately slows things down to save battery; choose Balanced or Best performance when plugged in.
Install updates in System Settings › General › Software Update, and update your apps from the App Store.
MacBooks: check System Settings › Battery. If Low Power Mode is on, your Mac runs slower to save battery. Set it to Never or Only on Battery.
Adware and hidden crypto-miners can eat your processor quietly. Signs include pop-up ads, a new browser homepage or search engine, and the fan running hard when you're not doing anything.
Open Windows Security from the Start menu, go to Virus & threat protection and run a Quick scan. For a deeper check, choose Scan options › Full scan.
macOS has built-in malware protection, but adware still gets in through downloads. Remove apps and browser extensions you don't remember installing, and for a second opinion run the free version of Malwarebytes for Mac.
If everything above is done and it's still slow, the computer may simply be short on power for what you ask of it. Two things matter most:
- Drive type. An old spinning hard drive (HDD) is the single biggest cause of slowness in older computers. Switching to a solid-state drive (SSD) can make it feel new.
- Memory (RAM). 8 GB is the practical minimum today; 16 GB is comfortable for heavy browsing and multitasking.
Check yours: in Task Manager, open Performance. Click Disk 0 to see whether it's an SSD or HDD, and Memory to see how much you have and how much is in use.
Check yours: choose Apple menu › About This Mac to see the memory. All Macs from roughly the last decade use SSDs. On Apple silicon Macs, memory can't be upgraded.
As a final step before upgrading, Settings › System › Recovery › Reset this PC with Keep my files reinstalls Windows while keeping your documents. You'll need to reinstall apps.
- Back up your files, then consider an SSD or memory upgrade at a local repair shop, which is often far cheaper than a new computer.
- If the fan is loud and the computer feels hot, dust buildup may be making it overheat and slow itself down. A repair shop can clean it.
HABITSKeep it running fast
Restart once a week
Clears stuck processes and lets updates finish installing.
Watch what starts with your computer
New apps often add themselves to startup. Check the list every few months.
Keep 15% of your drive free
Turn on automatic cleanup so you don't have to think about it.
One antivirus is enough
Two security apps fight each other and slow everything down. Windows Security is fine for most people.
FAQCommon questions
Why is my computer suddenly so slow?
Something is usually running in the background: an update, a virus scan, cloud sync catching up, or one app gone haywire. Task Manager or Activity Monitor (step 2) shows you which.
Will adding more RAM make my computer faster?
Only if you're running out of it. If memory use regularly sits above about 85%, or the Mac's Memory Pressure graph is yellow or red, more RAM will help. If not, it won't make a noticeable difference.
Is restarting better than shutting down?
On Windows, yes. Fast Startup makes “Shut down” save part of the system state, so problems can carry over. Restart always starts fresh. On a Mac, both are fully fresh starts.
Do I need a “PC optimizer” or “Mac cleaner” app?
No. Everything they do can be done with the built-in tools in this guide, and many of these apps push paid upgrades or slow your computer down themselves.
Why is my laptop slower on battery?
Battery-saving modes deliberately reduce performance to make the charge last longer. Plug in, or change the power mode in step 6.
Is my computer just too old?
If it still has a spinning hard drive and 4 GB of RAM or less, it will struggle with modern websites and apps. An SSD upgrade often helps a lot; beyond that, it may be time to replace it.