Correct RAM configuration

Discussion in 'Mac Pro' started by sawihsiwi, Aug 25, 2012.

  1. sawihsiwi macrumors newbie

    Feb 1, 2010
    I recently upgraded my RAM and keep getting a prompt that my module are placed incorrectly, plus some of them are not recognized at all. I have a Mac Pro 2x2.4 GHz quad core and the following RAM modules:
    2 x 8GB OWC sticks
    2 x 4GB OWC sticks
    4 x 1GB original ones that came with the computer.

    I would like to know two things:
    1. What is the ideal configuration with all sticks?
    2. In case slot 1 is defective (which it might be) what would be the best scenario then?

    Just to avoid confusion, please provide in your answer the slot numbers (1-8) in which the memory needs to be installed in.

    Thank you very much for your help.
  2. avemestr macrumors regular

    Aug 14, 2012
    It seems weird to mix various RAM sizes and makes. It's hardly recommendable and will only give you headaches. So the ideal configuration is to go out and buy 4 extra 8GB OWC sticks similar to those you already have, and throw away your 4GB and 1GB sticks.
  3. Phrygian, Aug 25, 2012
    Last edited: Aug 25, 2012

    Phrygian macrumors regular

    Nov 26, 2011
    As someone who considers himself not very knowledgable about mac hardware upgrades and such and has had to teach myself a lot, I can give you some information that i learned regarding Mac pros and ram.

    First off, your mac pro requires a specific type of memory stick. You can't just purchase any type of ram. If you go to "about this mac" under your apple icon (top left), and then click on more detail, there will be a description of which series mac pro you have. Mine for example is "early 2008" which is also referred to as a 3.1. Therefore my mac requires 800 MHz DDR2 FB-DIMM memory modules. I have also seen my ram referred to as 800MHz ECC Mac Pro Memory

    This is a site where you can buy ram specific to your computer, however i liked the site i used better... and i'm not finding it at the moment. OCW is good but i found better deals elsewhere.

    This mac rumor guide will give you a general idea of how to instal the ram

    Once you have the correct memory, the modules should be placed on the risers in a specific configuration. Your mac manual will describe this, as will youtube tutorials, however the general idea is that riser A's first two slots need to be filled with memory. (Each pair should be identical in number, in other words two 1 gig modules, or at least im pretty sure thats the case.) Then you fill in riser B's first two slots, then riser A's last two slots, then riser B's last two slots. Again, i would suggest you find a tutorial or look in your manual and not trust my advice on this one, as i don't know your model and hey, maybe i'm wrong, but thats what i did.

    so when i look at my memory on my mac i have:
    riser A_________rise B
    slot 1--1g _____________2g
    slot 2--1g_____________ 2g
    slot 3--2g_____________ 2g
    slot 4--2g_____________ 2g

    Edit: I believe what you should try is the following configuration. Again, please check your use manual and/or video tutorials specific to your model.
    riser A_________rise B
    slot 1--1g _____________1g
    slot 2--1g_____________ 1g
    slot 3--4g_____________ 8g
    slot 4--4g_____________ 8g

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