Windows only seeing 3Gb on a new 4Gb 24" iMac?

Posted:
in Current Mac Hardware edited January 2014
Hi, I've kept away from Windows for the best part of a decade but decided to boot camp vista ultimate on my new 2.4Ghz, 24", 4Gb, 320Gb iMac - for some reason windows only recognises 3Gb of memory - is that right?

Comments

  • Reply 1 of 6
    yamayama Posts: 427member
    Are you using the 32bit or 64bit version of Vista?



    I belive there is a limitation in the 32bit version which limits you to using 3GB of RAM (even though theoretically you should be able to access 4GB).



    edit: found a Microsoft knowledgebase article about it: http://support.microsoft.com/kb/929605



    Quote:

    The reduction in available system memory depends on the devices that are installed in the computer. However, to avoid potential driver compatibility issues, the 32-bit versions of Windows Vista limit the total available memory to 3.12 GB. See the "More information" section for information about potential driver compatibility issues.



    They also list a workaround which involves going into the BIOS and playing around with some settings. However, trying to do that on a iMac that uses EFI instead of BIOS might be a bad idea... I don't know exactly how Boot Camp fools Windows into thinking there is a BIOS, or if there is some kind of legacy BIOS emulation in EFI. Either way, it's not something you want to mess with unless you don't mind breaking your new iMac
  • Reply 2 of 6
    chopper3chopper3 Posts: 293member
    Quote:
    Originally Posted by yama View Post


    Are you using the 32bit or 64bit version of Vista?



    I belive there is a limitation in the 32bit version which limits you to using 3GB of RAM (even though theoretically you should be able to access 4GB).



    edit: found a Microsoft knowledgebase article about it: http://support.microsoft.com/kb/929605



    Yes it is the 32-bit version as boot camp only deals with 32b versions afaik. Thanks for the tip-off anyway.
  • Reply 3 of 6
    yamayama Posts: 427member
    Quote:
    Originally Posted by Chopper3 View Post


    Yes it is the 32-bit version as boot camp only deals with 32b versions afaik. Thanks for the tip-off anyway.



    Interesting, I didn't realise Boot Camp only worked with 32bit versions of Windows... I wonder if this will change with Leopard. I know that VMWare Workstation on Windows and Linux has experimental support 64bit OSes - anybody kow if Parallels or VMWare Fusion do as well?
  • Reply 4 of 6
    Quote:
    Originally Posted by yama View Post


    Interesting, I didn't realise Boot Camp only worked with 32bit versions of Windows... I wonder if this will change with Leopard. I know that VMWare Workstation on Windows and Linux has experimental support 64bit OSes - anybody kow if Parallels or VMWare Fusion do as well?



    Fusion support 64-bit guests. Parallels does not.
  • Reply 5 of 6
    seek3rseek3r Posts: 179member
    Quote:
    Originally Posted by Chopper3 View Post


    Yes it is the 32-bit version as boot camp only deals with 32b versions afaik. Thanks for the tip-off anyway.



    Boot-camp's *drivers* are 32bit, but all boot camp itself is is a mechanism for booting bios-based OSs on the Apple version of EFI and a pretty gui, I have XP x64 and Debian AMD64 booting perfectly fine on the Mac Pro I'm typing this one for example.
  • Reply 6 of 6
    yamayama Posts: 427member
    Quote:
    Originally Posted by palter View Post


    Fusion support 64-bit guests. Parallels does not.



    Cool, thanks for the info.
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