Myth: run 'sudo purge' regularly to free up RAM — via Howard Oakley, The Eclectic Light Company
MythNeeds adminmacOS 14 Sonoma and later
purge empties the disk cache, the copies of recently used files macOS keeps in RAM so they open quickly. It's meant for benchmarking, not maintenance. After a purge, the next things you open have to come from disk again, so it can make your Mac briefly slower.
What to do instead
- Don't add purge to scripts or run it 'to clean up'. Let macOS manage memory itself.
- If the Mac feels slow, open Activity Monitor's Memory tab and look at Memory Pressure rather than free memory (see 'Check memory pressure, not free RAM').
- Quit the specific app that's using lots of memory instead.
Howard Oakley's write-up explains that purge forces the disk cache to be flushed and has little to do with memory management. Apple notes that cached files help performance when you reopen an app.
Sources
- Q&A: Pointless purges — by Howard Oakley, The Eclectic Light Company
- View memory usage in Activity Monitor on Mac — by Apple Support
- Source reviewed
- 2026-11-02
- Link checked
- 2026-11-02
- Tested hands-on
- Not by Oddbyte.Me
Oddbyte.Me hasn't tried this on every macOS version, so keep the undo handy.