I have a Macbook Pro (early 2011) running OS X Lion and while running a few apps that only take up, say, 200 MBs of space each (Xcode, Spotify, and Photoshop), my wired memory shoots up to 1.4GB, my active to 4.39GB, inactive to 2.18GB, and free 28.3MB. Note: this happens with different apps at times, not just a combination of these three.

The issue is so bad that programs lag so badly that there are seconds of delays when, for example, clicking on a label to edit text. Even the Spotify music starts to stutter, but the CPU usage isn't very high (less than 10% used).

Is this common? Besides restarting, is there something I can do to fix this? Perhaps it's something not relating to memory?

  • What does "200 MBs of space each" mean? Photoshop is around 400 MB and its support files well into GB. As for your memory issues, it's impossible to diagnose performance problems with the limited information you have provided. Stats on memory allocation from Activity Monitor tell you nothing. AT's RZISE (real memory) reports are useless too as collectively, they don't jive with the number found under "Used" memory. Xcode and Ps are very big apps that consume a lot of resources. What are your values Page ins and Page outs? Ideally, you want Outs to be <= 5% of Page Ins (to avoid trashing).
    – user10355
    Commented Dec 14, 2011 at 18:59
  • Do you have 10.7.2 installed?
    – EmmEff
    Commented Dec 14, 2011 at 19:00

2 Answers 2


Apple documentation on memory says that

The inactive list contains pages that are currently resident in physical memory but have not been accessed recently. These pages contain valid data but may be released from memory at any time.

inactive + free can be considered as the free memory

  • Hmm, so is this not a RAM problem? I was reading on Lion hard drive permission problems. Going to follow some of the steps and I'll report back.
    – Derek
    Commented Dec 14, 2011 at 18:57

Free memory is wasted memory.

OS X and other modern operating systems like Windows Vista and Windows 7 fill empty memory with stuff that you might use... so if you do use it, you don't have to wait for it to be pulled from disk.

The fact you have 2.18 GB of "inactive" RAM means your operating system has kept 2 GB of stuff in there that you might use again but would also drop at a moment's notice to replace with something else (your Active and/or Wired RAM would grow to consume the Inactive.) This replacement takes zero (or at least very close to zero) extra time compared to leaving the RAM sitting there with nothing in it.

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