Mac Pro Memory Configurations

Discussion in 'Mac Pro' started by dpaanlka, Jun 22, 2007.

  1. dpaanlka macrumors 601


    Nov 16, 2004
    I'm thinking of buying this 4GB memory kit from OWC. It's two 2GB modules. But I don't know exactly how to figure out the optimum memory configuration when I install them.

    Should I install them on the same daughtercard as my stock 2x512 modules? Should they be installed in the same location as said modules, but on the other daughtercard? Should they replace the 512s? Should I even keep the 512s??

    Confused! :confused: :eek:
  2. Eraserhead macrumors G4


    Nov 3, 2005
    I wouldn't think it matters much, if you have another 2x512 sticks or another 2x2gb sticks then they should share a daughtercard.
  3. SDDave2007 macrumors regular

    Apr 12, 2007
    Follow the instructions on the inside of the MacPro side cover

    One Pair of Ram : top card ... inside pair of slots

    Two Pair of Ram : top card .. inside pair of slots
    bot card .. inside pair of slots

    Three Pair : same as two.. 3rd pair on top card
  4. CanadaRAM macrumors G5


    Oct 11, 2004
    On the Left Coast - Victoria BC Canada
    Install then in descending order of size:

    Your two largest go in Riser A Slots 1 and 2
    Your next two go in Riser B Slots 1 and 2
    Your next two in Riser A Slots 3 and 4
    Last two in Riser B Slots 3 and 4


    (Ok, you just had to keep on reading, din't ya?)
    Here is some nit picking detail that doesn't pertain to the original post.

    The only exception might be if you have 4 of one size and 2 larger ones, it might be a smidgen faster to put the four in 1&2 1&2 for 256 bit access however -- it depends on how your programs use memory - the 3 & 4 slots are slower to access than the 1 & 2 slots, so that's why generally you want your largest memory in first, under the theory that if you can keep all or most of the memory access in 1 & 2, you won't have the additional latency of 3&4

  5. 4God macrumors 68020


    Apr 5, 2005
    My Mac
    This should help.
    However, when using different sizes Apple recommends that you install the
    larger size in the first two slots on riser A and the smaller in the first two slots
    on riser B.

    In your case, you would install the pair of 2Gb sticks in the first two
    slots on riser A and your pair of 512's in the first two slots of riser B.

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