Only 8 out of 16GB ram is visible in Windows 7 64bit

Discussion in 'Windows, Linux & Others on the Mac' started by TheSandman2236, Feb 28, 2013.

  1. macrumors 6502

    Joined:
    Mar 11, 2008
    Location:
    Atlanta, GA
    #1
    I'm running a brand new Late 2012 i7 iMac with Fusion Drive, 16GB of ram, etc. I just put a bootcamp partition with WIndows 7 Pro x64 on the Fusion Drive today and after all the drivers and updates were applied the system does not allow usage of the full 16GB installed in the machine (this was also the case prior to driver/updates installation). Can anyone supply a solution or a reason why this is the case?
     
  2. macrumors 6502

    Joined:
    Jan 18, 2012
    #2
    Aren't some versions of Windows 7 RAM limited. You may need ultimate or pro to go above 8gb of ram?
     
  3. TheSandman2236, Feb 28, 2013
    Last edited: Feb 28, 2013

    thread starter macrumors 6502

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    #3
    I'm using Windows 7 Pro x64 -- plus I have 16GB RAM on my Windows Desktop.
     
  4. macrumors 6502

    Joined:
    Sep 10, 2012
    Location:
    The Real Northern California
    #4
    No.

    The RAM limitation in Windows has to do with 32-bit versus 64-bit. The limit of addressable memory in 32-bit is 4GB. Because of the way in which Windows uses memory and begins addressing memory for processes, it works down from 4GB, so a 32-bit Windows installation with 4GB of memory may show anywhere between 3.5GB down to 2.8GB of system memory.

    The OP is very likely facing a limitation of the BootCamp environment in which he has Windows installed and running.

    I've never had the occasion to play with BootCamp, so that is as far as I can speculate.
     
  5. macrumors 603

    Joined:
    Mar 29, 2008
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    Seattle
    #5
    No issues here with 32GB RAM 2012 iMac running Windows 7 64bit.
     

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  6. macrumors newbie

    Joined:
    Jan 23, 2013
    #6

    I have the exact same machine and problem.

    I have two different brands of RAM (stock ram & Crucial ), could this be the reason maybe?
     
  7. macrumors regular

    Joined:
    Dec 29, 2011
    #7
    It's a windows thing as my brothers have pcs and they get same, windows only uses 8gb even after they've added 16gb to their pc's. i think pc's use virtual memory mostly why they put on hdd an unallocated space to use as virtual memory. that my thoughts i maybe wrong.
     
  8. WilliamG, Feb 28, 2013
    Last edited: Feb 28, 2013

    macrumors 603

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    Seattle
    #8
    How are you determining that Windows is only using 8GB? I disabled all virtual memory in Windows 7 64bit, since 32GB is more than I would ever need.
     
  9. macrumors 6502a

    Joined:
    Feb 16, 2010
    #9
    Type msinfo32.exe in the start menu. It should give the physical and virtual memory status.
     
  10. macrumors 6502

    Joined:
    Jan 18, 2013
    Location:
    Columbia, SC
    #10
    A *possible* solution... as a user with Administrator rights, run 'msconfig'

    Select Boot tab, and then Advanced Options, then Maximum Memory. If it's checked, uncheck it and do a cold reboot.
     
  11. macrumors 68000

    Joined:
    Aug 20, 2010
    #11
    I have 2 machines that show my full RAM under W7 professional x64 - 24Gb and 16Gb - so I doubt it is a Windows limitation, as long as you're running a 64bit version.
     
  12. macrumors 6502

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    Sep 10, 2012
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    The Real Northern California
    #12
    Hey WmG, you're running with BootCamp, nes pas?
     
  13. macrumors 603

    Joined:
    Mar 29, 2008
    Location:
    Seattle
    #13
    Yep.
     
  14. thread starter macrumors 6502

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    Location:
    Atlanta, GA
    #14
    Looks like I may have two bad RAM slots. Swapping it out tonight :/
     

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