64-bit 32-bit Snow Leopard Confusion

Discussion in 'macOS' started by Sothos, Mar 13, 2010.

  1. Sothos macrumors member

    Dec 4, 2009
    Hi, I'm on a MacBook Air 2.13GHz/128GB SSD. I just have a few questions regarding the 64-bit Snow Leopard

    First off, would a 64-bit kernel benefit me, particularly with my system with fixed memory?

    I've just realized that most of my core operating system processes run in 64-bit even if I am running in a 32-bit kernel. I don't quite understand how that would affect my performance. Should I force all my apps to run in 32-bit mode? And if so, how would I go about doing that?

    Thanks everyone. :D
  2. Denarius macrumors 6502a


    Feb 5, 2008
    Gironde, France
    The only scenario where the 64-bit kernel is used by default is with XServes, which often have very high demands for memory, drive space and the like. Some machines can boot in 64-bit kernel by holding down 6+4 on startup, but it's just a gimmick really of no real value other than a curio. Defaulting to 64 bit kernel can also have complications with drivers. Stick with 32 bit kernel for a quiet life in my view.
  3. Cinder6 macrumors 6502


    Jul 9, 2009
    By modifying boot.efi, you can trick your system to run in 64-bit kernel mode, so long as your hardware actually supports it. But you don't really see any performance increase. I'm using it right now for really lame bragging rights and because nothing actually broke when I switched it.
  4. MacDawg macrumors Core


    Mar 20, 2004
    "Between the Hedges"
    Have you checked out the Guide?
    Has a lot of good information
  5. Riemann Zeta macrumors 6502a

    Feb 12, 2008
    I run 10.6 with the pure x64 kernel and have seen some (small) performance increases overall with no compatibility issues, so I have stuck with it. This is on a Penryn MBP with 4GB of RAM. If I recall, the max amount of RAM for the Air is locked at 2GB. So, there would probably be even less of a performance difference (i.e. probably way too small to notice).

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