Max Glenister

Software & Servers • 2 min read Plain text

Dealing with crappy memory management in OS X

Using a lot of memory-intensive programs throughout the day, such as Virtualbox virtual machines, Photoshop and numerous browsers each with a couple of handfuls of tabs, you come to realise how bad the memory management in Mac OS X is.

Take the following screenshot, this is after having closed a bunch of programs because my 2011 iMac (with 12 GB of RAM) was crawling and reporting “11 MB” of free memory.

OS X is being stupid – or rather, it’s probably trying to be quite smart, but it’s failing to be smart, so it’s being stupid. I’ve got 12 GB of RAM, and OS X is gasping for some RAM, but it has half of it set as “Inactive”.

What does this mean? Well, to put it simply, when you close an application OS X retains that application in memory so that next time you open it up it opens really fast. This is great if you’re only using your computer to browse Facebook in Safari, or if you’re playing with Photobooth, but for any real-world tasks such as virtualising Windows 7 using Virtualbox, it’s not so great.

Luckily there is a terminal command that will free up this “Inactive” RAM:

$ purge

Now, I’m pretty sure that you need to have the OS X Developer Tools installed to use purge, but if you’re in the kind of situation that warrants purging your memory, you’ve probably already got it installed.

The result after running purge?

Wonderful.

  • UX & Design · shares #macos
    Making GIMP feel less like punishment

    GIMP has always had an interface problem. I’m not blaming the GIMP team (they’ve built something powerful on a shoestring). They’ve been clear they’re not interested in copying Photoshop wholesale; their FAQ argues that designing around actual user research beats imitating someone else’s interface decisions. Fair enough in principle, but coming from years as a Photoshop user, that design still feels hostile to me. I’m just one user story out of many they’ve had to design for, but it still expects me to learn its own way of doing things rather than offering a config closer to what I’m used to out of the box.

    June 2026 • 2 min read
  • Software & Servers · shares #guide
    Replacing the macOS audio switcher with SwiftBar

    The built-in audio output menu in macOS has always felt a bit limited. The icons aren’t very helpful, the device names can’t be customised, and if you’ve got a few different outputs, it becomes tricky to quickly tell what’s what.

    October 2025 • 3 min read
  • Tinkering · shares #guide
    Installing Chrome OS on a Late 2009 MacBook

    I’ve got an old 2009 MacBook 6,1 (A1342) kicking about in my office that I’ve been playing with on and off lately.

    April 2022 • 2 min read

Discussion

  • A

    This was incredibly helpful, thank you!

Join the conversation

Reply from your own site with a Webmention (how?).

Webmentions last fetched 14 November 2026, 10:07