Only seeing 1GB, why?

Discussion in 'Mac Pro' started by ted400, Nov 16, 2009.

  1. ted400 macrumors newbie

    Nov 30, 2007
    I have an older Mac Pro (G5 Dual 1.8's)...The problem is I have four sticks of 512MB installed however when I look at "About This Mac" only two sticks show up in slots 1 and 2. I have all the same make/model of RAM and have even tried to move the sticks around into different slots, still same thing slot 1 and 2 are the only one's recognized. Slots 3 and 4 say they are "Empty" when in fact they are occupied with the same RAM as 1 and 2.

    ...I know this configuration is a little "light" for the Pro standards these days, but this is my file server and doesn't require a ton of overhead, I'd just like to get it running a bit faster, and instead of getting two 1GB sticks I'd like to figure out why the 2GB I have in there don't work.

  2. gugucom macrumors 68020


    May 21, 2009
    Munich, Germany
    A Power Mac dual CPU needs pairs of RAM on both RAM banks A and B. The RAM slots need to be filled from the inside to the outside with equal pairs.
  3. ted400 thread starter macrumors newbie

    Nov 30, 2007
    Right, I have the same RAM in every slot, its the same make model and size so they are "paired".
  4. wpc33 macrumors 6502


    Jul 2, 2006
    Vancouver, BC
    When that happened to me, with 4x1GB in a G5, and 2GB showing, I rotated the sticks to troubleshoot. When that didn't fix it, I found the one or two that were to blame, and RMA'd them to OWC. The replacements worked immediately.
  5. ted400 thread starter macrumors newbie

    Nov 30, 2007
    Hmm...good call. I'll Tech Tool and see if I have a bad stick in there. Just the bump in the right direction I was looking for.

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