16GB Modules in 2009 Quad core

Discussion in 'Mac Pro' started by linuxcooldude, Jan 30, 2017.

  1. linuxcooldude macrumors 68020

    Mar 1, 2010
    Is it possible to put 4 X 16GB modules for a total of 64GB? Thanks.
    --- Post Merged, Jan 30, 2017 ---
    Checking with OWC they said only 3 X 16GB Module configuration is possible.
  2. owbp macrumors 6502a


    Jan 28, 2016
    Belgrade, Serbia
    Well, OWC is kind of famous here ;)

    Yes it is possible if you're using dual processor capable Xeon, and you can go "only" to 56GB if you're using single processor capable Xeon. So, let's say you have 3,33GHz 6 core CPU in your mac:
    - if your CPU is W3680 then only 56GB (3x16 and 1x8)
    - if your CPU is X5680 then you can go to 4x16GB

    Screen Shot 2017-01-30 at 7.57.27 PM.png
    All is explained here: http://forums.macrumors.com/threads/mac-pro-cpu-compatibility-list.1954766/
  3. linuxcooldude, Jan 30, 2017
    Last edited: Jan 30, 2017

    linuxcooldude thread starter macrumors 68020

    Mar 1, 2010
    Thanks, helps out a lot and a few configurations I was not aware about. OWC website says you can't mix 16GB with different size modules? Thats with the 56GB configuration 3 X 16GB & 1 X 8GB Modules.
  4. Surrat macrumors 6502


    Jun 20, 2014
    United States
    Remember on your mac pro you will get maximum performance by using only 3 memory modules. Using 4, or different size modules to get 56GB, will slow it down... not a lot, but its there.

    3 x 16GB would give you max performance.
  5. h9826790 macrumors G4


    Apr 3, 2014
    Hong Kong
    The real limitation is that you can't mix RDIMM with UDIMM, size doesn't matter.
    --- Post Merged, Jan 31, 2017 ---
    It's true if the memory usage is less than 48GB. Otherwise, not necessary correct.

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