iMac late 2013 Memory failure !

Discussion in 'iMac' started by IA64, Nov 7, 2014.

  1. IA64 macrumors 6502

    Joined:
    Nov 8, 2013
    #1
    I tried Apple Diagnostic tests today out of curiosity for the first time and got an Error PPM003 related to faulty memory module.

    I never experienced any crash or panic. Boot time is 7 seconds and system is really smooth.

    I have 32GB installed of RAM but I am not sure which one is faulty.

    How can I find out which one ? I guess it's a dual channel so not possible to test them one by one.

    Any hint please ?
     
  2. IA64 thread starter macrumors 6502

    Joined:
    Nov 8, 2013
    #2
    So I tested 2 stick or RAMs and no errors found.

    I tested the other 2 sticks and no errors found.

    I installed the 4 sticks and tested again, now I have memory failure.

    Does it mean the motherboard is defective ?
     
  3. troy14 macrumors 6502a

    Joined:
    Mar 25, 2008
    Location:
    Las Vegas (Summerlin), NV
    #3
    Did you test them one by one? I wouldn't test two at a time. Maybe test one by one in each different slot. Time consuming, absolutely. Or take it in to Apple.
     
  4. IA64 thread starter macrumors 6502

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    Nov 8, 2013
    #4
    OK but what would be different ?
     
  5. nrubenstein macrumors 6502

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    Aug 5, 2008
    Location:
    Washington, DC
    #5
    Is the RAM all matching spec? Post a pic showing the labels on all four modules.
     
  6. IA64 thread starter macrumors 6502

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    Nov 8, 2013
    #6
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  7. IA64 thread starter macrumors 6502

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    Nov 8, 2013
  8. IA64 thread starter macrumors 6502

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    Nov 8, 2013
  9. WilliamG macrumors 604

    Joined:
    Mar 29, 2008
    Location:
    Seattle
    #9
    Try with 3 sticks in there. Try slots 1, 2, 3, and then 2, 3, 4. That would help narrow it down to socket issue or not.
     
  10. Chippy99 macrumors 6502a

    Joined:
    Apr 28, 2012
    #10
    4 sticks is always more difficult to drive than 2 sticks and any marginal problems in terms of compatibility or quality will often show up with 4 sticks and not with 2. CL9 is faster than Apple's regular specs as well - but you knew that. 4 sticks at CL9 is pushing it, and instability like this is not uncommon.

    Your only option is to return all the memory and start again with 4 new sticks imho. And if you can try a different brand altogether, I'd do that. Is CL9 really that important to you? I'll bet it's not noticeably faster unless specifically benchmarking it. 4 stick at CL10 or CL11 would be a lot more likely to be stable.
     
  11. IA64 thread starter macrumors 6502

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    Nov 8, 2013
    #11
    Well I purchased the RAMs last year and never had any problem when I run memtest under OSX in single user mode.

    Now suddenly it's displaying errors. Even with 32GB installed, If i run memtest 16000 ( 16GB split into 8 GBs ), it doesn't show errors. Only when I test the full memory available.


    Also if it's returning errors, why I have never had any single crash sine more than 11 months ? Im puzzled.
     
  12. Chippy99 macrumors 6502a

    Joined:
    Apr 28, 2012
    #12
    I'm not at all surprised. As I say, compatibility is not a boolean thing. Things can be marginal and only show up is certain circumstances. 4 sticks puts much more load on the memory controller and it's obviously not able to drive all sticks at those timings with complete reliability.

    As to why it doesn't cause errors in OS X, well when you run things like Memtest and Apple's diagnostics, they stress the hardware much more. It's very common for computers to be stable in normal use but to fail Memtest (or Prime95 for that matter).
     

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