HT201191: Install memory in an iMac

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Joe Faber

Q: Not recognizing new memory

Hi there,

Just installed 4GB of new Crucial memory (a pair of 2GB memory). Installed both of them and booted machine back up, but it says that only 4GB is installed (which just reflects the old memory). I thought I had inserted the memory in far enough - seemed to snap into position and were just as far in as the existing memory. Would there be any other reason why the memory isn't being recognized? These were DDR3 PC3-10600 non-ECC at 1333Mhz.

iMac, Mac OS X (10.6.8), 2.8GHz core i5, 4 GB RAM, 27"

Posted on Feb 14, 2013 7:21 PM

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Q: Not recognizing new memory

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  • Helpful answers

  • by Miska_FL,

    Miska_FL Miska_FL Feb 14, 2013 7:34 PM in response to Joe Faber
    Level 2 (390 points)
    Feb 14, 2013 7:34 PM in response to Joe Faber

    Mac OS Version?

  • by Joe Faber,

    Joe Faber Joe Faber Feb 14, 2013 7:36 PM in response to Miska_FL
    Level 1 (119 points)
    Desktops
    Feb 14, 2013 7:36 PM in response to Miska_FL

    10.8.2

  • by Miska_FL,

    Miska_FL Miska_FL Feb 14, 2013 7:38 PM in response to Joe Faber
    Level 2 (390 points)
    Feb 14, 2013 7:38 PM in response to Joe Faber

    Remove the factory memory and add just the new memory see if it works.

  • by BDAqua,Helpful

    BDAqua BDAqua Feb 14, 2013 9:27 PM in response to Miska_FL
    Level 10 (123,765 points)
    Feb 14, 2013 9:27 PM in response to Miska_FL

    Is this Mac compatible RAM?

     

    Got a link to what you bought?

     

    ave you done a PRAM reset, CMD+Option+p+r...

     

    http://support.apple.com/kb/HT1379

     

    In fact, do 3 in a row, takes a bit of time.

     

    In Sytem Rerport>HardwareMemory, what shows...

     

    Memory Slots:

     

      ECC:          Disabled

     

    BANK 0/DIMM0:

     

      Size:          2 GB

      Type:          DDR2 SDRAM

      Speed:          667 MHz

      Status:          OK

      Manufacturer:          0x7F7F7F7F7FF70000

      Part Number:          0x00004B363435365536314535363637460000

      Serial Number:          0x00000000

     

    BANK 1/DIMM1:

     

      Size:          4 GB

      Type:          DDR2 SDRAM

      Speed:          667 MHz

      Status:          OK

      Manufacturer:          0x7F7FFE0000000000

      Part Number:          0x4542453431554638414244412D38472D4520

      Serial Number:          0x2401D4C8

  • by Joe Faber,Solvedanswer

    Joe Faber Joe Faber Feb 21, 2013 6:54 AM in response to BDAqua
    Level 1 (119 points)
    Desktops
    Feb 21, 2013 6:54 AM in response to BDAqua

    So finally got around to trying to fix this. RAM was advertised as mac compatible (bought through B&H, but double-checked on Crucial's website). I reseated the memory and swapped positions between the factory installed Samsung 2GB modules and the new RAM modules. This time it worked and machine recognized the full 8GB. Not sure what the magic was that finally did it, but thanks for the suggestions.

  • by BDAqua,

    BDAqua BDAqua Feb 21, 2013 9:30 AM in response to Joe Faber
    Level 10 (123,765 points)
    Feb 21, 2013 9:30 AM in response to Joe Faber

    Good work, sometimes just a reseating or 2 is what's needed.