Vista equivalent to the /3GB boot.ini switch

Discussion in 'Windows Vista General Discussion' started by Tim Anderson, Oct 19, 2006.

  1. Tim Anderson

    Tim Anderson Guest

    My computer only has 2GB of RAM installed and I can see all of this memory
    so this question has nothing to do with not being able to see installed
    memory.

    My question is thus:

    "How do I get a LARGEADDRESSAWARE application to see more than 2GB of
    virtual memory?"

    On XPSP2 and Windows Server 2003, you can add the /3GB boot.ini switch to
    let LARGEADDRESSAWARE applications access memory beyond the 2GB limit. I
    cannot find any equivalent option in the Vista boot configuration that will
    enable this. This has nothing to do with PAE (which allows access beyond the
    4GB limit) and does not require a 64bit OS. This is specifically for 32bit
    CPUs running a 32bit OS and there is no requirement for any specific amount
    of physical RAM. How do I enable this for Vista (on a 32bit CPU and x86 OS)?

    If the answer is -- "you need a 64bit OS" -- then IMO Vista is a step down
    in functionality and limits functionality on very capable x86 platforms.

    Thanks,
    Tim
     
    Tim Anderson, Oct 19, 2006
    #1
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  2. Tim Anderson

    AJR Guest

    Tim - Quoted from your question "...to see more than 2GB of virtual
    memory?".." - Virtual or RAM?
     
    AJR, Oct 19, 2006
    #2
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  3. Tim Anderson

    Tim Anderson Guest

    Quoted from my original post "My computer only has 2GB of RAM installed and
    I can see all of this memory so this question has nothing to do with not
    being able to see installed memory."

    To restate in other words:

    "How can I get an application to see more than 2GB of VIRTUAL memory?"
     
    Tim Anderson, Oct 19, 2006
    #3
  4. Tim Anderson

    deebs Guest

    I'd guess that Vista does stuff a different way to XP. In other words:
    there is no direct comparison.

    Running either 32 bit or 64 bit Vista RC1 on this machine with 3 Gig of
    RAM shows very similar results.
     
    deebs, Oct 19, 2006
    #4
  5. David Sanders, Oct 19, 2006
    #5
  6. Tim Anderson

    Tim Anderson Guest

    If an application is comiled with the /LARGEADDRESSAWARE option AND XPSP2 is
    booted with the /3GB option, that application's virtual address space is 3GB
    instead of 2GB regardless of how much memory you have installed. It's called
    virtual memory because it does not necessarily point to any physical memory
    address. Normal applications don't have this requirement but high-end,
    memory intensive application do and the solution for the typical
    desktop/mobile workstation is to used the aforementioned settings. Vista
    does not do "stuff a different way to XP" on a 32bit CPU (which cannot run a
    64bit OS -- XP, Vista, or otherwise), but there are applications that are
    going to expect the XP functionality. FWIW, you can have 256MB of RAM
    installed in your system, but each 32bit application has an address space of
    at least 2GB or 3GB is the OS provides the option and the application is
    compiled to use it. If you don't understand this distinction, it is probably
    not important to you, but for the business application that are expecting to
    have users loading Vista in November(?) are going to be disappointed unless
    they shell out bucks for another workstation. This is not a performance
    issue -- its a maximum virtual address space issue.

    So far, I have not seen any response indicating that Vista x86 will support
    LARGEADDRESSAWARE applications.
     
    Tim Anderson, Oct 20, 2006
    #6
  7. Tim Anderson

    Tim Anderson Guest

    Tim Anderson, Oct 20, 2006
    #7
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