Riser B RAM no longer recognized on 3,1

Discussion in 'Mac Pro' started by sigmadog, Sep 5, 2014.

  1. sigmadog macrumors 6502a

    sigmadog

    Joined:
    Feb 11, 2009
    Location:
    near Spokane, WA
    #1
    I just noticed today that my trusty 3,1 is not recognizing the RAM loaded on Riser B. In System Information, it shows Riser A full with 8GB, but Riser B shows as empty.

    Here's the configuration of my 14GB RAM:

    Riser A: 2GB | 2GB | 2GB | 2GB
    Riser B: 1GB | 1GB | 2GB | 2GB

    I've pulled Riser B, inspected and cleaned and re-seated the RAM and placed the riser back in the slot nice and tight, but it's still not showing up in System Info.

    Like I said, I just noticed this today, so I don't know how long this has been going on. I'll try switching some of the RAM sticks to determine if they are dead or if the culprit is Riser B (which I suspect).

    Anyone have any other ideas?
     
  2. sigmadog thread starter macrumors 6502a

    sigmadog

    Joined:
    Feb 11, 2009
    Location:
    near Spokane, WA
    #2
    I just swapped out all the RAM (those on Riser A went to Riser B and those on B went to A), and now all the RAM on Riser A is not being recognized.

    So it appears I have some dead RAM, unless there's something I'm missing...
     
  3. DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #3
    According to your first post, your suspected set has a pair of 1GB, and a pair of 2GB.
    Remove the 1GB pair, and move the pair of 2GB to DIMM slots 1 and 2. Leave that pair of 1GB out, and test your MacPro with that configuration.

    - BTW, if you don't already know, the risers are also interchangeable. -

    If your pair of 2GB still are not recognized, then remove that pair, and put the pair of 1GB in the same slots, and test again.
    If you still get nothing, Move the pair from the good riser in DIMM 1 & 2 to the same slots on the other riser. Move the pair you removed from other riser to the same slots on your good riser. (Need I say, be sure to keep track of which RAM pairs are where, easy to get confused. I suggest temp labels on the RAM sticks to recall the original positions, but you can use whatever method works… )
     
  4. sigmadog thread starter macrumors 6502a

    sigmadog

    Joined:
    Feb 11, 2009
    Location:
    near Spokane, WA
  5. sigmadog thread starter macrumors 6502a

    sigmadog

    Joined:
    Feb 11, 2009
    Location:
    near Spokane, WA
    #5
    Okay. I removed the 2(1GB) and moved the 2(2GB) into slots 1 and 2. Restarted and all the RAM is now showing up: 12GB.

    Thanks for your help, DeltaMac.

    On closer inspection, the 1GB pair have a bit of greasy goo on the heat sink wings. Makes me wonder if something on them has been melting.

    I think I'll replace them with a couple 2GB from eBay... the cost doesn't seem so bad, and I'll get a tiny bump to 16GB.
     

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