Booting into 64-bit Snow Leopard

Discussion in 'Mac Pro' started by Topper, Sep 3, 2009.

  1. Topper macrumors 65816

    Topper

    Joined:
    Jun 17, 2007
    #1
    .
    I know this has been somewhat covered before but...

    Should I be booting into 64-bit Snow Leopard?

    I have a 2008 Mac Pro with 16GB of memory. I mostly run Photoshop CS4, X-Plane, QuickTime 7 Pro, Compressor and FCP6.

    I know you hold down the 6 and 4 keys but is anyone using either "Happy Cat", "K64Enabler 1.0.1", or "32- or 64-bit Kernel Startup Mode Selector 1.2.3" to enable 64-bit Snow Leopard?
    .
     
  2. gr8tfly macrumors 603

    gr8tfly

    Joined:
    Oct 29, 2006
    Location:
    ~119W 34N
    #2
    Yep. It's been covered quite a bit.

    Snow Leopard is enabled for 64-bit out of the box. It's capable of running 64-bit apps without any modification.

    The methods you mention are so you can boot into the K64 kernel - something you most likely don't need or want (for compatibility reasons). Whether you use the 32-bit or 64-bit kernel has no bearing on SL's ability to run 64-bit applications and their ability to address large amounts of RAM. The applications you mention aren't 64-bit yet, anyway.
     
  3. Topper thread starter macrumors 65816

    Topper

    Joined:
    Jun 17, 2007
    #3
    I just got done reading this from AppleInsider:

    "Apple's 64-bit kernel requires both a 64-bit processor (a Core2 Duo or better) and 64-bit EFI.

    However, running a 64-bit kernel on these machines is of limited benefit. While there are certain advantages with the move to a 64-bit kernel, including new security enhancements, the primary benefit of a 64-bit kernel is being able to directly work with significantly more than 4GB of RAM, something that most existing consumer Macs and generic PCs can't do anyway.

    For this reason, Snow Leopard also defaults to running its 32-bit kernel even on consumer models with 64-bit EFI. This prevents mainstream users from running into problems related to incompatible kernel extensions and device drivers (such as printer software), which aren't yet 64-bit.

    This problem has helped repress the popularity of the 64-bit editions of Windows over the last several years, but won't hold up 64-bit Mac adoption because there is only one edition of Snow Leopard, one that runs on all Intel Macs and simply adjusts itself to the limitations of the given hardware.

    Users who want to run the new 64-bit kernel on late modeled Macs (pretty much anything released after early 2008) can do so by booting with the 6 and 4 keys held down. If you're wondering whether your Mac has a 64-bit EFI firmware, you can type the command "ioreg -l -p IODeviceTree | grep firmware-abi" into the Terminal. The response will identify the machine as either having 32-bit or 64-bit EFI.

    What Snow Leopard does do is bring all Core2 Duo, 64-bit Macs (pretty much everything sold since 2007) up to speed with 64-bit system apps, from the Finder and Dock to iChat and Mail to background processes such as launchd and the system-wide spell checker. Running the 64-bit kernel or not, the singular version of Snow Leopard always runs 64-bit apps when running on 64-bit hardware; in contrast, no 32-bit editions of Windows can run 64-bit apps, even on 64-bit capable hardware.

    Snow Leopard's upgrade to 64-bit system apps provides an overall speed boost due to limitations in the original design of Intel's 32-bit chips; the move to the new 64-bit x64 processor model, originally developed by AMD, solves these issues. Moving to 64-bit apps on other processor families, such as PowerPC, does not yield the same boost, but rather only incurs additional overhead, one of the reasons Snow Leopard is Intel-only."

    That kinda says what you say but it also says that 64-bit kernal can work with more than 4GB of memory?
    .
     
  4. crazzyeddie macrumors 68030

    crazzyeddie

    Joined:
    Dec 7, 2002
    Location:
    Florida, USA
    #4
    That means that the Kernel itself can use more than 4GB of memory. Not your apps.

    I read an article that basically said you don't need more than 4GB for the Kernel until your machine has somewhere over 100GB of RAM... Currently, with 4GB of RAM on my MBP, the Kernel uses about 200MB of RAM. You can see how much yours is using in the Activity Monitor under "Real Mem."
     
  5. gr8tfly macrumors 603

    gr8tfly

    Joined:
    Oct 29, 2006
    Location:
    ~119W 34N
    #5
    That's one of the reasons it's only Xserves that boot to K64 by default. Also, they tend have limited 3rd party kexts. That limits the possibility of 32<>64 conflicts.

    ArsTechnica has a great in-depth look into SL. Part of it is a discussion of the K64 question: http://arstechnica.com/apple/reviews/2009/08/mac-os-x-10-6.ars/5
     
  6. kittiyut macrumors regular

    kittiyut

    Joined:
    Oct 28, 2007
    #6
    It's kinda cool to be able to do so (boot into 64bit kernel), however, VMware and Parallels won't run. I also can not connect to my external SATA drives - no 64bit drivers yet for Sonnet E4P card (drivers coming next month though). Everything else seems to be running fine.
     
  7. Infrared macrumors 68000

    Infrared

    Joined:
    Mar 28, 2007
    #7
    You can't use this (or any other >= 4GB graphics card) without a
    64-bit kernel:

    http://www.nvidia.co.uk/object/product_quadro_fx_5800_uk.html

    Apple doesn't offer a 4GB graphics card now. How long before they
    do? I leave the speculation to you :)
     
  8. gugucom macrumors 68020

    gugucom

    Joined:
    May 21, 2009
    Location:
    Munich, Germany
    #8
    The next big thing in displays will be QuadHD. They are already working on that for military apps and everything they do there eventually ends in the consumers lap when it ages. So EFI32 will be a bad bottleneck in the future.
     
  9. MacVidCards Suspended

    Joined:
    Nov 17, 2008
    Location:
    Hollywood, CA
    #9
    As of 10.6, the OS doesn't even know what to do with a 2 Gig Graphics card. (See my "2 Gig Bug" thread...same issue was in 10.5.7/8, now in SL)

    That guy with 2 Gig 4870 found same issue I did.

    So it seems that they aren't playing with large cards yet, or the bug would have been caught and fixed by now.
     
  10. 2002cbr600f4i macrumors 6502

    Joined:
    Jun 21, 2008
    #10
    Here's a thought/question....

    In OSX, does the video card memory get an identical sized buffer in kernel space memory? If so, I could see a 2GB card causing a problem with a 32 bit kernel space limited to 4GB.

    Not saying that's wht's happening, just taking a stab in the dark.
     
  11. Infrared macrumors 68000

    Infrared

    Joined:
    Mar 28, 2007
    #11

Share This Page