Now you see it, now you don't...disappearing RAM

Discussion in 'Mac Pro' started by Hmac, Dec 30, 2007.

  1. Hmac macrumors 68020

    Joined:
    May 30, 2007
    Location:
    Midwest USA
    #1
    On my Mac Pro 4-core 3ghz, I get different About-This-Mac screens and profiles on different boot-ups. I do have 8 gig of Crucial RAM installed in addition to the 1 gig of Apple RAM the machine came with. I haven't quite figured out what's happening to that particular 2 gig RAM. Seems to disappear randomly. I do have Boot Camp set up and running Windows XP, no Parallels on this machine.

    The machine runs perfectly. Never had a crash, never had a kernel panic. The problem is always in DIMM 1 of Riser A.

    [​IMG] [​IMG]


    [​IMG] [​IMG]

    Any idea what's happening here?
     
  2. mad jew Moderator emeritus

    mad jew

    Joined:
    Apr 3, 2004
    Location:
    Adelaide, Australia
    #2
    Have you checked to see that it's inserted properly?
     
  3. hms84 macrumors regular

    Joined:
    Jul 28, 2007
    #3
    try to swap with the other RAMs
    and use if the problem proceeds that means your RAMs are OK

    but the problem is either Hardware or Software of the pro it self.
     
  4. Hmac thread starter macrumors 68020

    Joined:
    May 30, 2007
    Location:
    Midwest USA
    #4
    Thanks for the reply. I did switch the problematic RAM in A1 and A2 with the RAM in B1 and B2. Initially, everything went back to 9 gigabytes and stayed for awhile....so I thought maybe it had just needed to be reseated. Then, I booted into Windows XP for awhile. When I booted back into OSX, I found that I was back to 7 gig RAM and now the mis-read RAM was in B1 and B2. I'll give Crucial a call. Seems pretty strange to me, but I have to think there's some kind of problem with the RAM itself rather than the machine.

    [​IMG]
    [​IMG]
     
  5. JNB macrumors 604

    JNB

    Joined:
    Oct 7, 2004
    Location:
    In a Hell predominately of my own making
    #5
    It's pretty obvious that the RAM is faulty - your one basic troubleshooting procedure (swaping RAM location) proved that fairly conclusively. Granted, RAM shouldn't report one size then another, it should be expected to work or fail, period. Just replace it.
     
  6. makku macrumors member

    Joined:
    Mar 22, 2006
    #6
    Did you swap the risers or just the memory modules? I hope having the memory module replaced works for you.
     
  7. hms84 macrumors regular

    Joined:
    Jul 28, 2007
    #7
    YAHHH!!
    Swapping is the best trouble shooting technique that I use allot at work HeHe :)
    Replace these RAMs
    Glad it worked with you...!
     
  8. pprior macrumors 65816

    Joined:
    Aug 1, 2007
    #8
    I had similar problem (different RAM maker). Was not getting any errors, but noted that my 2GB chips were being reported as 1GB chips intermittantly. Opened the Mac pro and the riser lights for the ram were lit. Swapped and made no difference.

    New ram swap from OWC and things were back to normal. As a bonus, the temps also went down pretty dramatically. Not sure why.

    Sounds like bad chips - swap 'em out.
     
  9. nikiski macrumors regular

    Joined:
    Oct 30, 2007
    Location:
    Hong Kong, or Surrey, BC, Canada
    #9
    I agree with the two posters that the RAM is faulty. I once had an old PC and the RAM size wasn't being reported consistently (It was Kingston RAM) and once I had them replaced things are back to normal.

    The OP should demand to get those two modules replaced. Hope it'll work out for you. :)
     
  10. darwinian macrumors 6502a

    darwinian

    Joined:
    Jan 4, 2008
    Location:
    In R4, more or less

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