Must have ram installed incorrectly: 2x2x2GB reads as only 4GB

Discussion in 'Mac Pro' started by marklight, Mar 7, 2008.

  1. marklight macrumors 6502

    Joined:
    Apr 6, 2006
    #1
    shows up as 1GB - 2GB - 1GB

    even though all three modules are 2 GB. I'm sure it's a really dumb installation problem, but thanks for any help.
     
  2. Mastershredder macrumors member

    Joined:
    Jan 27, 2006
    #2
    Mac Pro RAM needs to be installed in pairs.
     
  3. marklight thread starter macrumors 6502

    Joined:
    Apr 6, 2006
    #3
    Yea that's what I was thinking. I ordered 4 GB (2X2) , and I thought that my mac pro would have come with 2GB (1X1), but instead it just came with a single 2GB chip. So I figured that it would probably be something with pairing seeing how it was shrinking down each stick to 1GB.
     
  4. Firefly2002 macrumors 65816

    Joined:
    Jan 9, 2008
  5. surf4peace macrumors newbie

    surf4peace

    Joined:
    Dec 8, 2007
    Location:
    U.S.A.
    #5
    Interesting. So the implication here is that if you have a stand alone stick of RAM, the pairing rules do not apply? I may be in your boat if that's the case...:eek: Oh well, we'll cross that bridge...
     
  6. MikeL macrumors 6502

    Joined:
    Jan 22, 2003
    Location:
    Bloomington, MN
    #6
    Did you happen to notice the second memory riser?
     
  7. bilbo--baggins macrumors 6502a

    Joined:
    Jan 6, 2006
    Location:
    UK
    #7
    I think you must have hit the nail on the head: the OP surely cannot have received a 2008 Mac Pro with a single 2GB module. There should be a 1GB module in each riser.

    If it really did come with a single 2GB module - which is almost never going to happen direct from Apple (and definitely wouldn't have been Apple's intention) - then you will need to return the memory and get it replaced. Buying a second module simply won't do - they need to be matched pairs and the only way to get a matched pair is to buy them as a matched pair. A single module is utterly worthless - it's of no use to anyone.
     
  8. Umbongo macrumors 601

    Umbongo

    Joined:
    Sep 14, 2006
    Location:
    England
    #8
    In addition to what others have said you will need to configure the memory so that both the 1GB DIMMs are on riser B and the 2GB DIMMs are on riser A, both sets occupying slots 1 and 2.
     
  9. Mitthrawnuruodo Moderator emeritus

    Mitthrawnuruodo

    Joined:
    Mar 10, 2004
    Location:
    Bergen, Norway
  10. bilbo--baggins macrumors 6502a

    Joined:
    Jan 6, 2006
    Location:
    UK
    #10
    That diagram is for the old Mac Pros, but it's the same for the new Mac Pro with 1 exception: the stock configuration of 2 x 1GB modules in the early 2008 Mac Pro actually has 1 module in slot 1 of each riser, not both together in one riser as shown in the diagram
     
  11. Mitthrawnuruodo Moderator emeritus

    Mitthrawnuruodo

    Joined:
    Mar 10, 2004
    Location:
    Bergen, Norway
    #11
    Which means that for the OP still might use it to place his RAM, right...?
     
  12. bilbo--baggins macrumors 6502a

    Joined:
    Jan 6, 2006
    Location:
    UK
    #12
    Yes. They just shouldn't expect to see 2 modules in the same riser as the stock configuration.
     

Share This Page