9 Replies Latest reply: Jul 31, 2010 3:39 PM by canbake
jghk Level 1 Level 1 (0 points)
This may be perceived by some as a dumb question, but I'd like to ask it anyway: what is the difference from operating my Mac in 32- or 64-bit? Are there any clear cut advantages of using 64-bit when using my Mac in a residential/office setting? By this, I mean, I am not doing any programing or designing ludicrous graphics. I know that some applications cannot operate in 64-bit, which can be quite annoying, especially BlackBerry Desktop Manager for Mac.

I have done my research, but I can't deal with all the technical jargon, so if someone could put it in simple terms for me, I'd very much appreciate it.

Thank you very much!


MacBook Pro 15" (3rd Generation), Mac OS X (10.6.4), Ordered off apple.com late June/early July 2009
  • andyBall_uk Level 7 Level 7 (20,485 points)

    unless you've some specific application or workflow that runs faster when running the 64 bit kernel, I'd stick to 32 bit, for the reasons you've mentioned.

    It does allow a single app to directly address over 4GB of RAM, which can be better for some apps, assuming you've over 4GB installed... but from your description of typical use, there's no reason to use it, and good reasons not to.
  • Taylor R Nelson Level 1 Level 1 (20 points)

    The entire computing industry is moving from 32-bit to 64-bit technology. Today’s Macs can hold up to 32GB of physical memory, but the 32-bit applications that run on them can address only 4GB of RAM at a time. 64-bit computing enables applications to address a theoretical 16 billion gigabytes of memory, or 16 exabytes. It can also enable computers to crunch twice the data per clock cycle, which can dramatically speed up numeric calculations and other tasks. Earlier versions of Mac OS X have offered a range of 64-bit capabilities.

    Nearly all system applications — including the Finder, Mail, Safari, iCal, and iChat — are now built with 64-bit code. So not only are they able to take full advantage of all the memory in your Mac, but the move to 64-bit applications also boosts overall performance. Together with other refinements and improvements in Snow Leopard, this means that just about everything you do — from launching applications like QuickTime to running JavaScript in Safari to opening image files — will feel faster and more responsive.

    So as you said, you aren't doing any programming or designing ludicrous graphics, but your Mac would still be better off running in 64-bit mode. Is your reason for wanting to run in 32-bit mode simply to be able to use the BlackBerry Desktop Manager for Mac? It should still working when running in 64-bit, but you could look at using Boot Camp perhaps to run it in Windows.

    Hope this helps

  • QuickTimeKirk Level 9 Level 9 (50,855 points)
    If you have 4 GB's of RAM, or less, there is no need to run in 64 bit mode.
  • BobHarris Level 6 Level 6 (15,575 points)
    A 32-bit Mac OS X kernel has been able to run 64-bit Applications since Mac OS X Leopard (10.5). With Mac OS X Snow Leopard (10.6), Most of the applications bundled with Snow Leopard have been built as 64-bit applciations, and RUN that way on both 32-bit and 64-bit Mac OS X kernels.

    You DO NOT need to boot into a 64-bit Mac OS X kernel to run 64-bit applications. If you have a 64-bit application it will be able to use more than 4GB of memory (if it wants to that is, and you happen to have the memory for it).

    If you run Applications -> Utilities -> Activity Monitor, you will see that many Snow Leopard applications are already running as 64-bit apps, and this is with your kernel booted as a 32-bit kernel.

    Today, the ONLY reason to boot your Mac OS X kernel as 64-bits is if you have a special device driver or kernel extension from a 3rd party which only works in 64-bit mode (this is extremely rare), or you are a 3rd party developer that is writing that 64-bit driver or kernel extension.

    The rest of us mortals can live very well with a 32-bit Mac OS X kernel, and use those memory intensive applications to our hearts content.
  • jghk Level 1 Level 1 (0 points)
    Thanks a lot guys! Really appreciate it!
  • canbake Level 1 Level 1 (0 points)
    I also have little understanding on this topic, so sorry for trivial questions, but I think I have a similar problem regarding Blackberry Desktop Manager (failing to recognise an update).

    Somewhere said that to resolve the Blackberry problem I had to run my mac in 32-bit mode, but I have no idea how to check if my os x 10.5.8 is running in 64 or 32-bit. I've seen a lot for Snow Leopard (press 3 and 2, or 6 and 4 on startup etc.) but nothing for Leopard. How can I check which kernel I'm using (system profiler doesn't say as far as I can tell)?

    If it is then running on the 64-bit kernel, how can I change it to the 32-bit one?

  • baltwo Level 9 Level 9 (61,945 points)
    AFAIK, there's no 64-bit kernel in Leopard, but I might be wrong.
  • BobHarris Level 6 Level 6 (15,575 points)
    Baltwo is correct. Mac OS X Leopard (10.5) uses a 32-bit kernel that is capable of running 64-bit applications.
  • canbake Level 1 Level 1 (0 points)
    Cheers, that clears things up. Thanks for the speedy reply too.