In the past month I am having some serious performance issues with my MacBook Pro (2008 model).
From the activity monitor, I get that the CPU usage is low (25%), disk usage is low (256 GB SSD drive, 50% free), network activity almost null.
What concerns me is system memory usage; of the 4GB RAM I have:

Free: 35 MB
Wired: 1.1 GB
Active: 1.9 GB
Inactive: 900 MB
Used: 3.99 GB
VM size: 650 GB
Swap used: 11 GB

I have nothing particularly heavy running. Could it be that, since I have not rebooted for a few months, some executables keep requiring memory slowing the system down (memory leak)?

Is it possible to recover unused but locked memory, without a reboot?

3 Answers 3


To answer your question, yes, applications and processes continue to start up and if you have not manually closed them or restarted the computer, you will be "losing" RAM. You can turn the inactive memory into free memory with this command in Terminal:

sudo purge

You can also run Activity Monitor to diagnose what apps are running and sort the list by most memory.

  • I do not reboot my computer often because it controls the nuclear power station in my basement ;-) The list of processes sorted by memory usage is: kernel_task (670 MB), followed by a list of 30 Google Chrome Renderer processes (7 MB - 300 MB). Now, Chrome creates a new process for every new tab, and I admit I have many of them open. However it should be the operating system in charge of moving some of these processes out of memory when not used for a long time or when resources get scarce.
    – Pietro
    Commented Sep 1, 2013 at 8:29
  • 2
    You can attempt to follow guides such as this one to "fix" the kernel_task issue, but your kernel task memory is not that high. Google Chrome has been known to be a memory hog. You can try bringing down Chrome's memory by killing and relaunching high memory consuming tabs using Chrome task manager. Overall, with Chrome, I find that you have to avoid too many tabs or extensions. Lastly, OS X Mavericks has features such as App Nap and Compressed Memory to solve these issues. Commented Sep 1, 2013 at 12:40

I noticed Chrome got mentioned.

Chrome too give me memory trouble. Especially when I open Google Drive, it just go crazy and eat all the RAM, and subsequently all the swap it can get.

Switch to Safari and regularly restart memory leaking applications. There's no other way round.


Reboot your machine. You'll free up both memory and disk space.

  • 1
    The question clearly states that rebooting is not an option.
    – Thecafremo
    Commented Sep 1, 2013 at 8:58
  • It doesn't say not an option, it asks if its possible without a reboot. The answer is not really without a reboot. Commented Sep 2, 2013 at 0:11

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