Memory Usage Issue - Advice Needed

Discussion in 'macOS' started by lbeck, Nov 13, 2010.

  1. lbeck macrumors 6502


    Dec 5, 2009
    Ok, so I'm trying to figure out why this is happening. I have a 6-core MP with 24GB of RAM and a SSD for my boot/apps.

    Earlier today I was running a few operations and checked activity monitor. I noticed that I still had over 14GB of RAM available but my page outs and swap usage were not 0 like they should be if you have available RAM.

    So I did some more testing, I opened up a bunch of apps, started ripping a DVD and then checked activity monitor. All was well, I had about 8GB of RAM still available and page outs and swap usage were 0. Then I decided to really test it so I opened up a 1GB file in photoshop and resized some of the layer sets. As soon as photoshop started to transform the layers my page outs and swap usage started adding up. Now it didn't up a bunch, I've attached a screenshot as the process was happening to show the results.

    So the question is ... I still had over 6GB of RAM left, why in the world would my mac pro start having to Swap memory?

    I can get it to happen everytime I have a bunch of stuff open and then perform a memory intensive task. And some might say,"well duh, that will happen" but swap usage should only happen if you dont have any available RAM.

    Can someone who has a decent amount of RAM and large apps like the adobe suite test this out as well? Open up a ton of apps and do a few heavy processes like modifying a 1-2GB file while ripping a DVD and check activity monitor to see if you get page outs and swap usage. Do whatever you need to do to stress the system. The goal would be to still have available RAM but verify if your system will start using swapping.

    Attached Files:

  2. VirtualRain macrumors 603


    Aug 1, 2008
    Vancouver, BC
    You might get better responses in the OSX forum as this is more a question about OSX memory management. However, I believe OSX can swap out stuff it feels may no longer be necessary at any time irregardless of free RAM. I also believe it's using free RAM for disk caching so even Free RAM is not really unused and may be put to better use in this way than clinging on to code libraries or data in RAM that the OS no longer considers all that relevant to the task at hand.
  3. lbeck thread starter macrumors 6502


    Dec 5, 2009
    Hmmm, interesting. Thanks for the tip as well, I'll ask a mod to move the thread. I'm so use to posting in MP.
  4. lbeck thread starter macrumors 6502


    Dec 5, 2009

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