How to Speed Up a Slow Mac (macOS 27 Edition)
Find what's slowing your Mac with Activity Monitor, trim login items, free up space and know when an older Mac has hit its limit. No cleaner apps needed.
Macs don't usually get slow for mysterious reasons. It's almost always one of five things: an app hogging resources, too many things launching at startup, a nearly full drive, too little memory for what you do, or a Mac that's simply getting old. Here's how to find out which, using only tools built into 
macOS.
Just updated to macOS 27? Wait a day
After a big update like macOS 27 (Golden Gate), your Mac spends hours reindexing Spotlight and Photos in the background. It's normal for things to feel sluggish for a day or so. Leave it plugged in overnight before judging.
Note: macOS 27 only supports Apple silicon Macs. Intel Macs stay on the previous version, which still gets security updates for a while.
1. Find the culprit with Activity Monitor
Open Activity Monitor (search for it with Cmd + Space).
- CPU tab: sort by "% CPU". Anything high while you're not using it? That's your problem.
- Memory tab: look at the Memory Pressure graph at the bottom. Green is fine. Yellow or red means you're running out of memory.
Common offenders: a browser with dozens of tabs, a stuck app, cloud sync uploading a big folder, or an old background helper app.
2. Trim login items
Go to System Settings → General → Login Items & Extensions. Remove apps you don't need launching at startup, and check "Allow in the Background" for helper apps you no longer use.
3. Free up storage
A Mac with only a few gigabytes free slows down noticeably. Aim for at least 15% free. Our guide to freeing up Mac storage shows where the space usually hides.
4. Tame your browser
Browsers are the number one memory hog. Close tabs you're not using, remove extensions you don't need, and consider Safari, which is particularly efficient on Macs. See which browser to use.
5. Restart regularly
Macs can go weeks without a restart, and small memory leaks add up. A restart once or twice a week clears them.
6. Check for updates
Apps and macOS updates often fix performance bugs: System Settings → General → Software Update, plus the App Store's Updates tab.
7. Know when it's the hardware
If Memory Pressure is constantly yellow or red during your normal work, your Mac doesn't have enough memory for how you use it. Macs can't be upgraded, so the fix is fewer open apps or a new Mac. See how much RAM you need and MacBook Air vs MacBook Pro.
What not to do
- Skip "Mac cleaner" apps. Many promise one-click speed-ups, do little, and push paid upgrades.
- Don't delete system files you don't recognize.
- Don't reset things randomly. Resetting settings rarely fixes slowness on modern Macs.
