2x1GB recognized as 2x512MB RAM

Discussion in 'Mac Pro' started by akadmon, May 18, 2007.

  1. akadmon macrumors 68010

    Joined:
    Aug 30, 2006
    Location:
    New England
    #1
    After getting a few beach-balls today, I checked the Activity Monitor and was shocked to see that it was only reporting 3GB RAM instead of 4GB (I have 2x1GB Techworks RAM and 2x2x512MB Apple OEM RAM). I next checked he System Profiler and it was showing that I have six 512MB sticks in there, and that all the RAM is OK. I ran TechTool and it did not find anything wrong with the RAM. I removed the Apple RAM and reseated the two 1GB sticks several times, but they're still being recognized as 512MB. :(

    Anybody have any idea what could be going on? If the RAM is bad, would it not simply fail to be recognized altogether? :confused:
     
  2. Spanky Deluxe macrumors 601

    Spanky Deluxe

    Joined:
    Mar 17, 2005
    Location:
    London, UK
    #2
    I'm no expert in such matters but I think I once heard that server (ECC) ram can run as a lesser size if it detects some of it being faulty. I may be barking up the wrong tree though. It does sound like you're going to have to dig out that warranty though. :(
     
  3. JayHM macrumors newbie

    Joined:
    May 18, 2007
    #3
    Did you ever figure this out? I'm experiencing the exact same thing. I installed four 1 gig sticks from transintl.com, and the two on the bottom riser are showing up correctly as 1 gig, but the two on the top riser show up as 512 meg each.
     
  4. leekohler macrumors G5

    leekohler

    Joined:
    Dec 22, 2004
    Location:
    Chicago, Illinois
    #4
    Whoa! I have no answers, but let me know when you get some. That is disturbing.
     
  5. akadmon thread starter macrumors 68010

    Joined:
    Aug 30, 2006
    Location:
    New England
    #5
    No answer. I called OWC and the tech immediately told me to send the RAM back for replacement. Unfortunately, I'm 1 day over the 30-day window for advance shipment, so I'll have to make do with only 2 GBs for a while.
     
  6. spork183 macrumors 6502a

    spork183

    Joined:
    Jul 30, 2006
    #6
    I'm asssuming it makes no difference, top or bottom riser?
     
  7. JayHM macrumors newbie

    Joined:
    May 18, 2007
    #7
    I think in my case, it ended up being just bad RAM. When I opened the case, I noticed the little red LED for DIMM 3 was lit (even though it showed up with status "OK" in System Profiler). DIMM 3 was one of the two that showed up with the incorrect size, so I'm sending both back.
     
  8. akadmon thread starter macrumors 68010

    Joined:
    Aug 30, 2006
    Location:
    New England
    #8
    Same thing no matter where.
     
  9. akadmon thread starter macrumors 68010

    Joined:
    Aug 30, 2006
    Location:
    New England
    #9
    I just took off the side panel with the computer running and sure enough a red LED on riser B is on (I moved the two 1GB sticks to riser B last time).

    It sucks that the System Profiler, rember and Techtool are incapable of detecting this failure.
     
  10. psychofreak Retired

    psychofreak

    Joined:
    May 16, 2006
    Location:
    London
    #10
    If possible, try putting them in another mac, to see if it spots a problem :)
     
  11. dethl macrumors regular

    Joined:
    Aug 28, 2002
    Location:
    Austin, TX
    #11
    I have a pair of 512s that read as 256s

    Your RAM is most likely bad if its reading as a lesser amount. I have a couple of 512s in my PM G5 that read is 256s. Tried testing them in my GFs dell and it refused to start up - always locked up at the memory test. Unfortunately I have no clue who made the RAM so I'm having to wait and save up money to replace the poor sticks.

    OTOH - with it reduced I really haven't seen much performance loss, aside from having less ram. Only problem I have is WoW freezing if I leave it on the login screen but I think thats more of a software issue than anything else.
     

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