Bootcamp only recognize 2.97GB's of RAM but I have 4GB!

Discussion in 'Windows, Linux & Others on the Mac' started by Jottle, Feb 27, 2009.

  1. Jottle macrumors 6502

    Joined:
    Oct 17, 2003
    #1
    Here's a weird problem. I have a 15'' unibody macbook pr with 4GB of RAM. In MAC OSX it shows that I have 4GB of ram, but in windows bootcamp when I click on the properties for my computer, it says I only have 2.97GB. Is this just an anomaly? Why isn't windows recognizing all of my RAM? Anyone else notice this issue?
     
  2. Steeph28 macrumors newbie

    Joined:
    Aug 8, 2005
    #2
    Seems like you have a 32-bit version of Windows which can only address up to 3 GB. If you install a 64-bit version it will see all four.
     
  3. Stridder44 macrumors 68040

    Stridder44

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    Mar 24, 2003
    Location:
    California
    #3
    You have a 32-bit OS. Right click on My Computer --> Properties. It'll say if it's 32/64 bit there.

    This is just one of many reasons why 32-bit OS's are dead. If you choose to make a move to 64-bit, then have no fear as 64-bit OS's are VERY stable and fast and drivers are plentiful.
     
  4. Jottle thread starter macrumors 6502

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    Oct 17, 2003
    #4
    Many thanks for the replies. I have the 32bit version of XP installed. Is there a 64bit version of XP? I'm not ready to make the jump to windows 7.
     
  5. Consultant macrumors G5

    Consultant

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    Jun 27, 2007
    #5
    xp 32bit > xp 64bit

    vista 64bit > vista 32bit
     
  6. Stridder44 macrumors 68040

    Stridder44

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    Mar 24, 2003
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    #6

    Bingo. Basically, if you're going to run XP, only bother with the 32-bit version. If you're going to run Vista, only bother with the 64-bit version.

    Usually I'd say go for Vista 64 but with Windows 7 slated to be released soon, don't bother now. If you can, just wait it out with what you have and get Windows 7 64-bit when it's released.
     
  7. FX120 macrumors 65816

    FX120

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    May 18, 2007
    #7
    A 32-bit OS can address a maximum of 4GB of memory, not 3GB.

    Of course this account for all memory in the system, not just system RAM. Every last bit of memory scattered about in your system also must be addressed, and eats up additional addresses that would otherwise be applied to system RAM.

    Graphics cards have the biggest impact these days, which can have large banks of dedicated on-card memory. These days it's not uncommon to have card in the 512MB range even on low end cards. All of this eats up available addresses that could otherwise be used for system RAM.

    In most systems today there are between 100-256MB of memory scattered about in the system in various other places as well, in very odd places like your wifi card for example.

    So the solution is to get more addresses! 2^64 addresses to be exact.

    Install Vista x64 and enjoy using all of your available memory.
     
  8. steveza macrumors 68000

    steveza

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    UK
    #8
    There is speculation that a near-complete release candidate will be publicly available around 11th April.
     
  9. Jottle thread starter macrumors 6502

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    Oct 17, 2003
    #9
    I'm not even going to bother with Vista. Too many incompatibilities for me. I can wait for 64bit Windows 7 all my life :)
     
  10. ayeying macrumors 601

    ayeying

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    Dec 5, 2007
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    Yay Area, CA
    #10
    Windows 7 IS Windows Vista. It's just a upgraded/faster/more stable version of it. You cannot upgrade from XP to 64-bit Windows 7. You will need to do a complete reinstall due to 32bit/64bit incompatabilities. Furthermore, even if you had 64-bit XP, you still cannot. Windows 7 can only be upgraded from Windows Vista.
     
  11. sushi Moderator emeritus

    sushi

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    #11
    Agree.

    From the sounds of it, Windows 7 will be a good release of Windows. No need to bother with Vista in the interim unless you need to.

    In the meantime, continue to use Windows XP.
     
  12. Jottle thread starter macrumors 6502

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    Oct 17, 2003
    #12
    Who said anything about upgrading? I'm going straight to 7 with a reinstall. All my bootcamp stuff is games anyways.
     
  13. sidewinder macrumors 68020

    sidewinder

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    Dec 10, 2008
    Location:
    Northern California
    #13
    This is not true. An OS that supports Physical Address Extension (PAE) can address more memory.

    Leopard, a 32-bit OS, supports PAE and has a 36-bit address space which is 64GB. No 32-bit process, application, driver, etc. can access more than 4GB of memory. 64-bit applications running under Leopard have no such limitation.

    Only some 32-bit server versions of Windows support PAE in regards to expanded memory address space. No desktop 32-bit Windows versions support more than 4GB of RAM, PAE enabled or not. Another oddity of 32-bit Windows OS releases is that each process is given a 4GB virtual address space. By default, 2GB is for the User process to use and 2GB is for the OS to use. This means that regardless of how much memory is in the a process can use no more than 2GB of it. Enabling PAE makes no difference. Both XP and Vista have an OS option that allows one to increase the User part of the virtual address space to 3GB. This option is generally not used because only applications specifically compiled to support are able to use the 3GB and it take 1GB away from the OS. Not a good thing generally.

    Processes on Leopard don't have this limit.

    Part of that 4GB physical address space is set aside to address BIOS, I/O cards, NICs, video/graphics cards, etc. For example, on my PC system running Vista, I have 2.8GB of addressable RAM even though I have 4GB installed. Why? 1.2GB of the address space is used to address BIOS, I/O cards, NICs, video/graphics cards, etc.

    In most systems, the address space used by BIOS, I/O cards, NICs, video/graphics cards, etc. is between .8 and 1 GB. Those with powerful graphics card would see numbers in the 1.2GB range.

    If I were running a 64-bit Vista on my PC, the address space for the BIOS, I/O cards, NICs, video/graphics cards, etc. would be outside of the address space the RAM in the system were mapped to. That would allow me to use all 4GB of RAM.

    S-
     
  14. DoFoT9 macrumors P6

    DoFoT9

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    Singapore
    #14
    from my short experience with windows 7, its MUCH better then vista :) windows 7 took a while to install but at least it didnt freeze like vista did :rolleyes:
     
  15. SajiAntony macrumors newbie

    Joined:
    Mar 1, 2009
    #15
    Windows Service Packs 1

    Hi

    Please install the service pack 1 for Windows Vista the system will show 4GB exact.
     
  16. DoFoT9 macrumors P6

    DoFoT9

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    Jun 11, 2007
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    Singapore
    #16
    he is running XP
     
  17. ayeying macrumors 601

    ayeying

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    Yay Area, CA
    #17
    It'll say it has 4GB but its still using 3.3GB.
     
  18. The Flashing Fi macrumors 6502a

    Joined:
    Sep 23, 2007
    #18
    Then you're going to hate Windows 7. Whatever is compatible with Vista will work with Windows 7 (for the most part, some UAC changes have messed with compatibility for a few programs, but it's an easy fix). Conversely, whatever's not compatible with Windows Vista won't be compatible with Windows 7.

    I believe if you buy an OEM copy of Vista after July 1st, you'll get a free upgrade to Windows 7 of the equivalent version of Vista (Say, you buy Windows Vista Home Premium, you'll be upgraded to Windows 7 Home Premium).

    Also, for Windows 7, all the features from the lower versions will be present in the upper versions. For instance, say if you buy Windows 7 Professional. You'll have all the features of Windows 7 Home Premium, and all the features of Professional.

    With Vista, if you bought Vista Business, you missed out on a few features in Vista Home Premium (such as Media Center), which really irritated me.
     

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