Mac Pro + Vista Business = only 2GB of RAM???

Discussion in 'Windows, Linux & Others on the Mac' started by The General, Apr 20, 2007.

  1. The General macrumors 601

    Joined:
    Jul 7, 2006
    #1
    I figured after everyone had the 2GB limit problem with XP that they would FIX it with Vista, but I guess I thought wrong! I have 4GB and Vista only sees 2GB!! What is wrong with Microsoft?? :mad:
     
  2. brand macrumors 601

    brand

    Joined:
    Oct 3, 2006
    Location:
    127.0.0.1
  3. The General thread starter macrumors 601

    Joined:
    Jul 7, 2006
    #3
    Eh? 3GB, but still.

    Is there a solution to this? I have 32-bit Vista Business edition, and 4GB of ram. It sees all 4 cores, but only 2 of my 4GB of ram.
     
  4. MRU Suspended

    MRU

    Joined:
    Aug 23, 2005
    Location:
    Other
    #4
    I have vista ultimate, and like you it only see's 2gb of memory in system profile.

    MacPro 2.66. 5gb Memory..
     
  5. LeviG macrumors 65816

    Joined:
    Nov 6, 2006
    Location:
    Norfolk, UK
    #5
    to get full access to 3GB or all the memory in windows you need either the /3GB switch (not got vista but in xp its added in the boot.ini) or the 64bit version. If youre running a 32bit os, it will allocate 2GB to programs and then 2GB to the os without the switch when theres 4GB for example
     
  6. sikzorro macrumors newbie

    sikzorro

    Joined:
    Apr 20, 2007
    Location:
    Karlsfeld, Germany
    #6
    could you please explain how i can use this switch to get my 3 GB of RAM work!

    Thanks
     
  7. BornAgainMac macrumors 603

    BornAgainMac

    Joined:
    Feb 4, 2004
    Location:
    Florida Resident
    #7
    That is messed up. I know a few people that brag about having 4 GB on their Windows boxes too. They have no clue about any setting or switch.

    Anyways, I brag back to them about my 8 GB and having a real OS. But I don't have any programs that can use more than 2 GB.
     
  8. TBi macrumors 68030

    TBi

    Joined:
    Jul 26, 2005
    Location:
    Ireland
  9. TBi macrumors 68030

    TBi

    Joined:
    Jul 26, 2005
    Location:
    Ireland
    #9
    The 3G switch only allows programs to allocate up to 3GB of memory, whereas other wise they are limited to only 2GB. This does not change how much memory windows can see.
     
  10. The General thread starter macrumors 601

    Joined:
    Jul 7, 2006
    #10
    1. I do not have a BIOS.

    2. 4GB works just fine in Linux and Mac OS X.

    It is most certainly a problem with Windows. :rolleyes:
     
  11. LeviG macrumors 65816

    Joined:
    Nov 6, 2006
    Location:
    Norfolk, UK
    #11
    its not a bios issue, most if not all modern bios' should be able to read 4GB, some intel only like 3GB iirc but its still more than 2GB. As a general rule 32bit xp can see 4GB but only utilises upto 3GB with programs due to it allocating memory for system components such as graphics, sound, pci bus etc - this is generally 2GB with 4GB installed when the switch is not added.

    Windows has a really weird configuration when more than 2GB is installed. Instead of increasing the amount of useable ram for programs (and as such visible in task manager etc) it shunts the extra onto the system ram. To claim back the extra gig when there is more than 2GB you need to apply the /3GB (this does not always work with all programs)

    link on the topic

    Also within windows the amount of ram visible can vary depending on what you use. System properties/Task manager only shows the usable ram for the programs (ie ram which is accessible within windows) so without the 3GB switch it will only show 2GB. Add the 3GB switch and it will show 3GB.

    I can confirm this is what happens as I run 4GB ram on 32bit windows xp pro with the 3GB switch.

    The above is working with xp

    EDIT - and to add the /3GB switch in vista 32bit - linky
     
  12. TBi macrumors 68030

    TBi

    Joined:
    Jul 26, 2005
    Location:
    Ireland
    #12
    Explanation of the /3GB Switch

    What people really need is the /PAE switch. This lets the processor use a special memory addressing mode which allows you to use all your available memory.

    Windows needs a bios to boot. EFI is a new version of the BIOS. Apple added bios emulation to the EFI layer to allow you to boot to windows.

    Although you are correct in saying you don't have a physical legacy bios, windows is using a virtual one. This virtual one may not be set up properly.
    Mac OSX tiger has 64-bit memory extensions. The kernel itself is 64-bit on 64-bit machines. The only reason it is not said to be fully 64-bit is because some of the library (quartz and what not) are still 32-bit. Thus on tiger you can run a 64-bit thread but only have a 32-bit interface.

    Are you using 64-bit linux? Linux handles memory differently from windows. Maybe it just uses the /PAE and /3GB switchs that windows has as options.

    No the problem is your lack of understanding on the issue.

    Actually linux shunts the memory to 3GB / 1GB just like windows with the /3GB switch. Linux just does this automatically whereas windows does not for compatibility reasons.

    Just for your information the upper limit for memory is about 3.5GB without PAE. There is only about 512MB allocated for other devices in a PC.
     
  13. LeviG macrumors 65816

    Joined:
    Nov 6, 2006
    Location:
    Norfolk, UK
    #13
    pae is installed automatically with the latest drivers, it is not added to my boot.ini in xp

    Are you sure about the 512MB used bit because that isn't the case with mine. The absolute maximum my memory could be after any deductions is 3.25GB (graphics card taking some extra and so only showing 3GB).
     
  14. slicedbread macrumors regular

    Joined:
    Nov 5, 2006
    #14
    to see more than 2GB of RAM in Windows, you will need a 64bit version of Vista or XP installed. 32bit XP (regular XP) and 32bit Vista will only show 2GB of ram.

    What TBi is saying is correct, and no amount of switches if configuration will change this. Its to do with the way Apple's EFI implements the legacy BIOS. 64bit OSes will see all your RAM, 32bit Windows will only ever see 2GB.

    Trust me on this, I have installed various Windows in BC loads of times, and the only way to get more than 2GB show up is to use a 64bit windows.
     
  15. cokersa macrumors member

    Joined:
    Apr 13, 2007
    Location:
    Kansas City
    #15
    I can also confirm that 32bit Vista won't see any more than 2GB. While there are some downsides of using 64bit Vista (lack of BT drivers for example), there are other benefits, including the ability to use more than 2GB. After a "less than successful" upgrade from XP to Vista Ultimate 32bit, I did a clean install of Vista Ultimate 64bit, and it works great. If you are interested, you might want to read the following link:

    http://www.wintellect.com/cs/blogs/...ta-x64-on-a-mac-pro-totally-awesome-dude.aspx
     
  16. The General thread starter macrumors 601

    Joined:
    Jul 7, 2006
  17. TBi macrumors 68030

    TBi

    Joined:
    Jul 26, 2005
    Location:
    Ireland
    #17
    Flame bait? Ya i thought your posts were that alright.
     
  18. balank macrumors newbie

    Joined:
    Dec 24, 2007
    #18
    MacPro Vista 2GB limit solved !!!!

    Folks, finally relief comes with Vista SP1. Some of us poor sods who bought the MacPro intending to use it as a Windows machine as well could not get Vista to see more than 2GB of RAM , however much RAM was actually present. I installed SP1 in the fervent hope that this would be fixed and IT HAS BEEN FIXED ! Now my system reports 4GB of memory and all is well with the world again!
     
  19. balank macrumors newbie

    Joined:
    Dec 24, 2007
    #19
    Clarification

    I forgot to clarify that I am using Vista 32 bit, not 64 bit and it now sees 4 GB of RAM. It is interesting to speculate whether it was an Apple problem that MS worked around or it was an MS problem all along. Since Dell and others have been delivering Vista 32 machines with 4GB of RAM, there is not enough evidence to suggest that it was an MS problem. On the other hand, with SP1 update the problem disappeared......Any ideas ??
     
  20. balank macrumors newbie

    Joined:
    Dec 24, 2007
    #20
    False Alarm

    Seems that Vista reports 4GB as present after SP1 upgrade but still uses only 2 GB of RAM. Sorry folks....Back to square one.
     
  21. blueged macrumors newbie

    Joined:
    Jun 30, 2008
    #21
    mac pro vista and ram

    Just read your post and would like to make sure I understand what you are saying.
    Here my problem. I am running Vista Ultimate 32 bit. I have a Mac Pro but perfer to use Vista. I have 8gb of ram however when I am in Vista which is most of the time, it only sees 2gb as you say.
    I do video editing and use Avid and its wants to see way more than 2gb of ram so it will not run.
    So you say if I do a clean/full install of Vista 64 bit then Vista will see more ram? and the EFI from the Mac Pro will not prevent Vista from seeing more than 2 gb of ram?
    Not sure if VMware is a solution because I am not sure how much ram it will allocate to Vista and it does not have firewire support...but it might be a temp solution.
    So then if I get a Vista 64 bit it will solve this ram problem?

    Jim
     
  22. Infrared macrumors 68000

    Infrared

    Joined:
    Mar 28, 2007
    #22
    Yes.
     
  23. Infrared macrumors 68000

    Infrared

    Joined:
    Mar 28, 2007
    #23
    Yes, that's the problem. Apple's BIOS emulation is rubbish. E.g.,

    (1) 1.99GB RAM limitation for Win32.

    (2) AHCI not enabled on Mac Pros.

    (3) VT-x not enabled on all Mac Pro cores.

    (4) Unable to boot off USB flash drives.

    And so on...
     
  24. blueged macrumors newbie

    Joined:
    Jun 30, 2008
    #24
    Ya I thought too. After the SP1 update, my performance setting in control panel said I now had all of my 8gb. However when I looked in Task manager I saw that Vista is only able to use 2gb.
     
  25. Stridder44 macrumors 68040

    Stridder44

    Joined:
    Mar 24, 2003
    Location:
    California
    #25
    Enjoy your 32-bit OS.

    Gotta agree though, EFI needs some work.
     

Share This Page