Memory disappeared?

Discussion in 'Mac Basics and Help' started by jellecoremans, Jan 18, 2008.

  1. jellecoremans macrumors newbie

    Joined:
    Jan 18, 2008
    #1
    Hello,

    I recently had my MBPro upgraded from 2GB RAM to 4GB.

    The 'About this mac' is saying I have 4GB.
    The Actuvity monitor is displaying the following
    [​IMG]


    Here too, it's displaying 4GB in total BUT
    the wired + active + inactive + free is only 3GB
    the wired part (red) is almoast half of the circle and it's only 1.44GB

    I am really wondering if I can use the 4GB

    thanks
     
  2. xUKHCx Administrator emeritus

    xUKHCx

    Joined:
    Jan 15, 2006
    Location:
    The Kop
    #2
    What mac do you have?

    Some macs can not use 4GB of RAM and show the same details in activity monitor.
     
  3. smogsy macrumors 6502a

    Joined:
    Jan 8, 2008
    #3
    for u uhcuk :p
     
  4. xUKHCx Administrator emeritus

    xUKHCx

    Joined:
    Jan 15, 2006
    Location:
    The Kop
    #4
    Not all MBPs were created the same so I was asking for more specifics as some can and some can't.
     
  5. SrWebDeveloper macrumors 68000

    SrWebDeveloper

    Joined:
    Dec 7, 2007
    Location:
    Alexandria, VA, USA
    #5
    Due to Kernel restrictions (commonly referred to as "addressing limitations") on some - not all - Mac's (this person plus my late 2006 iMac 20 2.16Ghz duo core) when you install 2x2GB (4GB) you only get 3.3GB usable. It's reported as 4GB.

    This is well documented on alot of quality sites that sell memory, including OWC and others, where once you select the chips for your Mac it will inform you of any limitations like this.

    The good news is you will still exploit interleaving (a 7-8% boost in performance for software supporting duo core threading technology) if the chips you inserted are paired (i.e. 2x2GB in each DIMM).

    -jim
     

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