Running purge command in the terminal to free the inactive memory isn't really what I think about Apple.

Lion isn't doing a great at all when it comes to free the inactive memory.
Free memory is reaching 16 MB and applications and the OS are becoming unresponsive, yet OS X isn't reclaiming the inactive memory.

After each session, I put the laptop to sleep. You can say that I shutdown my OS once a month. Unixes after all aren't created to be rebooted.

OS X Snow Leopard was pretty sleek, I don't know but it looks it is a Lion thing (maybe due iOS brought to Lion features).

Any better way to reclaim the inactive memory on Lion?
I got 4 GB of RAM


4 Answers 4


Yes, you can, one command only (run in Terminal):


And recheck inactive RAM

  • 1
    That is my first line :p
    – Chiron
    Aug 29, 2012 at 19:16

The real way I've made progress diagnosing this sort of issue is to use sysdiagnose to profile your system immediately after boot, then again before swap starts to get written and again when you note the slowdown.

Issuing purge is not effective with OS X virtual memory on Lion and muddies the waters to find the real culprit in terms of memory leaks or paging stress.

I've found that server Macs are generally stable for 6 months or more and don't need reboots before an update will force a reboot. Client Macs running software like Office, Adobe and even some of Apple's consumer products (or Pro apps) do not run perpetually like other UNIX and benefit from a reboot once a month or so to clear memory if you have issues with swap that cannot be isolated and ameliorated by sysdiagnose or other changes in usage.

  • sysdiagnose isn't available on Snow Leopard. I'd say a busy client Mac desktop should be restarted more often than once/month, depending on how hard you are pushing it and how many apps you are using. I'm experimenting now with purge to see if it will do the same thing as a restart or a logout/login. Mar 29, 2016 at 14:19

Probably not much better than what you are doing but I use iboostup occasionally when i wan t to free up some memory. I constantly struggling here with 2gb MBA and i use vmaware fusion for windows machine that just takes the memory from me. It has a couple other nice features too.



There are free apps on the Mac App Store that add a free-memory button to the menu bar for quick memory purging.

Search for "memory" in the MAS and choose what suits your needs.

Hope this is what you are looking for.

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