Max. amount of RAM for iMac core2 duo

Discussion in 'iMac' started by azscp, Aug 4, 2007.

  1. azscp macrumors member

    Nov 9, 2006
    What is the maximum amount of ram I can install in my 20" iMac core2 duo? Can she handle 4GB? Crucial states the max. amount per slot is 2GB. Just confirming before I purchase.

    Is crucial preferred over OWC, Samsung, Kingston or Micron?

    So many choices. I get a little confused.
  2. lancestraz macrumors 6502a


    Nov 27, 2005
  3. kaltsasa macrumors 6502a

    Jan 9, 2002
    Kellogg IA
    There's some sort of arbitrary hardware or software limitation capping the Core 2 iMacs at 3 Gigs. Theoretically they should handle 4, in reality its 2+1. I've got 3 gigs in my iMac and it's nice. Parallels runs like butter. I buy OWC RAM, they've always had good prices, good products, and good support. A great company.
  4. CanadaRAM macrumors G5


    Oct 11, 2004
    On the Left Coast - Victoria BC Canada
    It's a hardware limitation of the memory controller on the Core2Duo logic boards. You can physically install 4 Gb ( 2 x 2 Gb) but the memory controller can only make 3.3 Gb available to the OS, because certain hardware resource addresses hog the addresses between 3.3 and 4.0 Gb (note- they don't actually use the RAM, they just preempt the addressing in that area from use by memory)

    This is solved in the MBP Santa Rosa chipset, which can map those hardware addresses out of the memory space, and therefore can utilize the full 4 Gb RAM.
  5. 4God macrumors 68020


    Apr 5, 2005
    My Mac
    Has anybody tried this yet on a C2D iMac?
  6. jimbama macrumors newbie

    Oct 5, 2006
    The OWC website has the following:

    All iMac Intel Core 2 Duo models have two user-accessible memory slots for up to 3GB of total memory supported. Installing memory in pairs allows for maximum memory performance, although additional performance is also attained with the maximum 3GB Memory Configuration.

    Any real world difference between the two? I have always assumed that I would be best served by maxing out the RAM (1x 1GB + 1x 2GB) vs. matching pairs with less total RAM (1x 1GB + 1x 1GB).

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