How to run in 64-Bit Mode and Benefits?

Discussion in 'MacBook Air' started by alan111, Jan 18, 2011.

  1. macrumors regular

    Joined:
    Sep 17, 2010
    #1
    Hello,

    I tried booting into 64-bit mode by holding down the 6 and 4 key upon boot. I know I am not running in 64-bit mode because I checked under system profiler, software, 64-bit kernel and the value is at "no". Is there another way to boot into it?

    Also, what are the benefits to running in 64-bit mode? I currently have a 1.86ghz Air with 4gb RAM.

    Thanks
     
  2. macrumors G5

    jav6454

    Joined:
    Nov 14, 2007
    Location:
    1 Geostationary Tower Plaza
    #2
    Only faster math and algorithms. On a user level of thins, not much difference. On the encoding and workload side of things, huge difference and boost in speed.
     
  3. macrumors G5

    gnasher729

    Joined:
    Nov 25, 2005
    #3
    That's the advantage of 64 bit applications. But the MBA does not have to run in a "64-bit mode" to use 64 bit applications; any Macintosh with a 64 bit capable processor (basically anything built since 2007) can run any mix of 32 bit and 64 bit applications.
     
  4. macrumors 6502a

    Joined:
    Dec 7, 2007
    Location:
    Los Angeles / Boston
    #4
    But there's no performance/efficiency benefit to enabling the 64 bit kernel, correct?
     
  5. macrumors G4

    Joined:
    Oct 23, 2010
    #5
    A 64-bit kernel would give the kernel itself more efficient access to RAM and the x64 instructions, and theoretically can speed up some applications, but the biggest benefit of 64-bit is at the application level. Unlike Windows, OS X can run 64-bit applications on a 32-bit kernel, so Apple has chosen to boot most of its systems into the 32-bit kernel. The advantage of doing that is that you don't need separate device drivers for 64-bit systems the way you do for Windows.
     
  6. Boston007, Jan 19, 2011
    Last edited: Jan 19, 2011

    macrumors 6502

    Boston007

    Joined:
    Apr 9, 2010
    #6
    http://www.stupendous.net/archives/2009/08/31/why-you-dont-need-a-64bit-kernel/

    Unless you're using high end applications, and on a MBA I doubt you are, then running in 64-bit may not benefit you at all.
     
  7. macrumors G5

    gnasher729

    Joined:
    Nov 25, 2005
    #7
    Not on an MacBook (Air or otherwise). You can look at the kernel as one very highly specialised application; it is only there to support the apps doing the real work, so it shouldn't be doing much actual work. (It's like the janitor who has the keys to an office building where 10,000 people are working. He is very, very important, even though he doesn't do very much work himself. )

    64 bit kernel gets important when you have machines with 64 GB of memory or so, because the kernel needs memory to keep track of how those 64 GB are used, and at that size the 32 bit limits may get important.
     
  8. macrumors member

    Paradigm

    Joined:
    Feb 14, 2008
    #8
    Check out this link:
    http://www.overclock.net/mac/564147-how-enable-64-bit-default-os.html
     

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