Mountain Lion memory limitation tested

Discussion in 'Mac Pro' started by wallysb01, Aug 8, 2012.

  1. wallysb01 macrumors 65816

    Jun 30, 2011
    Hi all,

    After installing Mountain Lion on our "new" 12 core 2.4 Mac Pro with 128GB installed, I tested the 96GB limit that appears to have been in place since Snow Leapord (IIRC).

    From the picture attached, you can see the OS recognizes the 128GB in "About This Mac", however activity monitor only registers 96 GB. From my test of running a particular program that I knew would try and used all 128 GB of RAM, I'm seeing swapping once active memory reaches 96 GB.

    I guess we'll have to wait for 10.9 for >96 GB of RAM?

    Attached Files:

    • 2.jpg
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  2. parapup macrumors 65816


    Oct 31, 2006
    Is this a firmware imposed limitation or an OS one? If you boot Windows or Linux on it does all 128Gb get used?
  3. simsaladimbamba

    Nov 28, 2010
    What particular application uses that much RAM?
  4. ActionableMango macrumors G3


    Sep 21, 2010
    2009 and later MP will use all 128GB of RAM with 64-bit versions of Windows and Linux.
  5. wallysb01 thread starter macrumors 65816

    Jun 30, 2011
    Its a de novo genome assembly program called SOAPdenovo.

    And yes, booting to linux works for accessing all that RAM. It has nothing to do with the hardware...

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