Windows MEM

Discussion in 'Mac Pro' started by costabunny, Aug 23, 2008.

  1. costabunny macrumors 68020

    costabunny

    Joined:
    May 15, 2008
    Location:
    ~/bunny/
    #1
    Just curious as to why a mac pro with 10GB shows only 2GB with XP 32bit. it should show 3-3.5Gb surely? There cannot be that many devices on the BUS using 2GB of address space in a MAC Pro (the only changes from default spec are the 512MN 8800GT (there is half a gig) and a USB card (probably occupying about 256KB at most).

    In my old PC with a pari of 768MB 8800GTX cards windows XP found 2.25GB out of 4.

    anyone else seen this ? just curious, not looking for a 'fix'

    (No I am not gonna use XP64 cos I can't be bothered to mess around with my USB 5.1 headset).
     
  2. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #2
    You had to be difficult. :D :p

    I think it would lie in the addressing technique used by the memory controller. Memory sticks that use fewer chips won't be able to address entire stick since the chip is mapped in an 'all or nothing' manner'. This is just a guess, but seems fairly likely to me.

    I wouldn't touch XP 64bit either. ;) It has its own problems. Boot Camp doesn't seem to like it very well. :eek:

    You could always switch from XP 32bit to Vista 64bit. The entire system RAM would become available, and you could likely find the necessary drivers for your headphones. :D

    The driver situation has improved drastically, just as Vista has become stable enough to use at last. :)
     
  3. CWallace macrumors 603

    CWallace

    Joined:
    Aug 17, 2007
    Location:
    Seattle, WA
    #3
    I believe it has something to do with how Boot Camp emulates the PC BIOS that only allows Windows to see 2GB when running in 32-bit mode. The question has come up many times and some folks have been nice enough to provide detailed answers as to why it happens so a search of the forum should bring up the actual reason in detail.

    If you need more then 2GB of RAM in Windows, your best bet is to purchase and install an OEM version of Windows Vista Business or Ultimate. That will see all the memory in your system. A few folks have had success in finding the base drivers (video, network, chipset) on the web from the hardware manufacturers to run Windows XP 64-bit, but that OS really isn't "ready for prime time" in many respects. Apple supports Vista 64 with a full suite of drivers on the Mac Pro and MacBook Pro.
     
  4. costabunny thread starter macrumors 68020

    costabunny

    Joined:
    May 15, 2008
    Location:
    ~/bunny/
    #4
    I just dropped Vista64 (I have business ed.) as the USB 5.1 drivers are flakey at best. :(

    oh well it was just a curiosity so no harm, no foul. I'll stick with 2GB - its only until COD4 comes out nativly for MAC OS anyways.

    Thanks for the input guys
     

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