iMac Snow Leopard Ram Addressing

Discussion in 'iMac' started by bigboy99, Nov 13, 2009.

  1. bigboy99 macrumors 6502

    Joined:
    Nov 12, 2005
    Location:
    Sarasota, FL
    #1
    How much ram will my iMac (5,1) running 10.6.2 address? The limit was 3GB with 10.5.
     
  2. 300D macrumors 65816

    300D

    Joined:
    May 2, 2009
    Location:
    Tulsa
    #2
    3GB is all the machine supports and is capable of using.
    4GB can be installed, and there will be a slight performance benefit, but the machine will still only use 3GB of it.
    Its a hardware limitation, not software, because the logicboard has only 32-bit EFI.
     
  3. bigboy99 thread starter macrumors 6502

    Joined:
    Nov 12, 2005
    Location:
    Sarasota, FL
    #3
    Thanks for the clarification. I'm upgrading this week as the 1GB that came with the computer is ridiculous, and I thought it might be an OS issue. The specs indicate "if 4GB is put in, OSX 10.5 will recognize it as 4GB, but will still only address 3GB." I was hoping this might have been fixed in Snow Leopard, but as it's a hardware limitation no sense in buying the extra 1GB.
     
  4. TMRaven macrumors 68020

    TMRaven

    Joined:
    Nov 5, 2009
    #4
    32 bit supports up to 4 gigs of ram.

    2^32= 4,294,967,296 bytes (4.2 gigabytes) for 32 bit.

    Most systems either use 3gigs or 2gigs of actual ram though, because ALL of the computer's memory is shared for usage (such as video card memory), up to that 4 gig limit.
     
  5. bigboy99 thread starter macrumors 6502

    Joined:
    Nov 12, 2005
    Location:
    Sarasota, FL
    #5
    Can you ball park the performance increase I might see from adding the last GB (4GB total) even though only 3GB can be addressed at once?
     
  6. bigboy99 thread starter macrumors 6502

    Joined:
    Nov 12, 2005
    Location:
    Sarasota, FL

Share This Page