Mac Running Slow? 10 Fixes to Speed It Up

1Find and Quit the CPU Hog

One runaway process causes 80% of sudden slowdowns:

1. Open Activity Monitor (Applications → Utilities → Activity Monitor)
2. Click the CPU tab, then click % CPU to sort descending
3. If any process is using 80–100% CPU constantly, select it and click the X button to quit
4. Common culprits: Spotlight indexer (Spotlight indexing — temporary), macOS system manager (thermal throttling), browser tabs, and cloud sync apps

2Check Available Storage — Free Up Space

macOS needs 10–15% free disk space to function well. Below 5GB, performance degrades severely:

1. Apple menu → System Settings → General → Storage
2. If you have less than 10GB free, clear space immediately
3. Click Recommendations for macOS's own suggestions
4. Quick wins: empty Trash, delete Downloads folder contents, remove duplicate photos

3Reduce Login Items and Background Agents

Every app that launches at startup slows your Mac down — and many install background agents silently:

1. System Settings → General → Login Items
2. Remove everything you don't need running at startup
3. Also check: System Settings → General → Login Items → Allow in the Background — disable background activity for apps you don't use

4Restart (Don't Just Sleep)

Many Mac users never restart — just close the lid. Memory pressure builds up over days:

1. Apple menu → Restart (not just shut down or sleep)
2. After restart, open Activity Monitor → Memory tab → check Memory Pressure gauge
3. Green = healthy. Yellow/Red = not enough RAM for your workload

5Clear Browser Cache

Browser caches grow to gigabytes and slow down browsing significantly:

Safari: Safari menu → Settings → Advanced → check "Show Develop menu" → Develop menu → Empty Caches

Chrome: ⌘+Shift+Delete → select "All time" → check "Cached images and files" → Clear data

6Update macOS

1. System Settings → General → Software Update
2. Install pending updates — performance fixes appear in nearly every macOS release
3. If you just installed a major macOS update and your Mac is slow: wait 24–48 hours — background re-indexing and optimization runs automatically and will complete

7Reduce Visual Effects

Transparency and motion effects consume GPU resources — disabling them speeds up older Macs noticeably:

1. System Settings → Accessibility → Display
2. Enable Reduce Motion → ON
3. Enable Reduce Transparency → ON

8Rebuild Spotlight Index

A corrupt Spotlight index causes Spotlight indexer to run at 100% CPU for days:

1. System Settings → Siri & Spotlight → Spotlight Privacy
2. Click + and add your entire hard drive (Macintosh HD)
3. Wait 30 seconds, then select it and click – to remove it
4. This forces Spotlight to rebuild its index from scratch — takes 1–2 hours but fixes persistent CPU drain

9Reset SMC (Intel Macs)

A stuck SMC causes macOS system manager to throttle CPU as a heat protection measure — making the Mac feel extremely slow even when it's not hot:

1. Shut down completely
2. Hold Shift + Control + Option + Power for 10 seconds
3. Release and restart — SMC resets and CPU throttling clears

Apple Silicon (M1/M2/M3/M4): A full shutdown (30+ sec) achieves the same result — no key combo needed.

10Clean Reinstall macOS (Last Resort)

1. Back up with Time Machine first
2. Restart into Recovery Mode (⌘+R for Intel, hold Power for Apple Silicon)
3. Select Reinstall macOS — preserves your data
4. If still slow after clean reinstall, the SSD may be failing (check with Disk Utility → First Aid)