reel2reel
macrumors 6502a
I didn't realize my 2008 MP at work wasn't booting in 64-bit by default. Just changed the boot preference to do this by default now. Can't wait to see if it makes a difference (I've got 16 GB's RAM in there, too).
Got a tip for us?
Let us know
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Who boots in 64bit kernal?
- Thread starter mjsmke
- Start date
- Sort by reaction score
I didn't realize my 2008 MP at work wasn't booting in 64-bit by default. Just changed the boot preference to do this by default now. Can't wait to see if it makes a difference (I've got 16 GB's RAM in there, too).
that little ap called K64 makes it easy to jump back and forth ? no finger dance or setting anything ?
I've configured my MacBook Pro to boot into 64-bit by default by editing my com.apple.boot.plist. Works fine, Handbrake encoding is a bit faster, system seems a little more snappy. Even my Focusrite Saffire still works!
jedijoe
macrumors 6502
Integers are 32-bit in 32-bit or 64-bit, since Mac like 99% of UNIXes follow the LP64 model for 64-bit. long types are 64-bit on 64-bit and 32-bit on 32-bit. Integers are always 32-bit.
And neither has anything to due with whether the kernel is 32-bit or 64-bit.
reel2reel
macrumors 6502a
http://timesoftware.free.fr/k64enabler/
website for K64 Enabler
yes according to the developer it just saves you writing it in the boot plist
I know you can enable 64 mode and hold down the 32 also ?
saves editing it I guess 🙂
website for K64 Enabler
yes according to the developer it just saves you writing it in the boot plist
I know you can enable 64 mode and hold down the 32 also ?
saves editing it I guess 🙂
more bits for me
I roll 64bit on both of my machines, the Mac Pro shipped with 64bit as default, and I've changed my MacBookPro to startup in 64bit.
Since I'm a recent switcher so I can't say exactly that I've seen much difference since I didn't really spend a lot of time in 32bit on OS-X.
I haven't found a single application or device choke on being booted up in 64bit mode.
As a server nerd by day with a few decades of experience I'll tell folks that if they have more than 4GB installed they should boot 64bit unless they have a specific reason not too (i.e. hardware won't support it and/or some craptastic software can't handle it).
I roll 64bit on both of my machines, the Mac Pro shipped with 64bit as default, and I've changed my MacBookPro to startup in 64bit.
Since I'm a recent switcher so I can't say exactly that I've seen much difference since I didn't really spend a lot of time in 32bit on OS-X.
I haven't found a single application or device choke on being booted up in 64bit mode.
As a server nerd by day with a few decades of experience I'll tell folks that if they have more than 4GB installed they should boot 64bit unless they have a specific reason not too (i.e. hardware won't support it and/or some craptastic software can't handle it).
I'm running version 2 as 3 isn't a free upgrade. Booting in 32-bit is cheaper than paying for version 3 (although it's good to know that 64-bit is supported now).
Edit: VMware is currently running a promotion where you can upgrade to 3.1 for $10. I've just upgraded 🙂
sjinsjca
macrumors 68020
I boot my early-2010 MacBook Pro, fully stuffed with 8GB of RAM, using the 64 bit kernel. I use virtual machines heavily, and it makes a difference.
BUT: Tethering my iPhone via USB cable was first supported in Snow Leopard 10.6.3, and something broke it recently (I'm suspecting a recent iTunes update). I can still tether using Bluetooth, but that's slow. So, I sometimes boot in 32-bit just to tether with acceptable speed. That kind of sucks. I've posted a bug report at bugreport.apple.com.
But most of the time, I find 64 bit to be a bit snapper in most usage, and significantly more responsive in virtual machine use. As others have noted, it's not necessarily the 64-bitness that's the reason; Intel's adoption of AMD's 64-bit extensions results in some significant efficiencies. Reportedly, there are also some security benefits to running in 64 bit mode.
BUT: Tethering my iPhone via USB cable was first supported in Snow Leopard 10.6.3, and something broke it recently (I'm suspecting a recent iTunes update). I can still tether using Bluetooth, but that's slow. So, I sometimes boot in 32-bit just to tether with acceptable speed. That kind of sucks. I've posted a bug report at bugreport.apple.com.
But most of the time, I find 64 bit to be a bit snapper in most usage, and significantly more responsive in virtual machine use. As others have noted, it's not necessarily the 64-bitness that's the reason; Intel's adoption of AMD's 64-bit extensions results in some significant efficiencies. Reportedly, there are also some security benefits to running in 64 bit mode.
sjinsjca
macrumors 68020
You really ought to edit that post, as you later admitted you're using an old release of VMWare. The current version runs like a hose under 64 bit. It's very solid.
sjinsjca
macrumors 68020
Incidentally, the Wikipedia article on the x86-64 architecture has some key information about OS X in 32 vs. 64 bit mode. I've boldfaced some important bits:
http://en.wikipedia.org/wiki/X86-64
Mac OS X v10.6 is the first version of Mac OS X that supports a 64-bit kernel. However, with its first release (v10.6.0), not all 64-bit computers are currently supported. The 64-bit kernel, like the 32-bit kernel, supports 32-bit applications; both kernels also support 64-bit applications. 32-bit applications have a virtual address space limit of 4 GB under either kernel.
The 64-bit kernel does not support 32-bit kernel extensions, and the 32-bit kernel does not support 64-bit kernel extensions.
Mac OS X v10.5 supports 64-bit GUI applications using Cocoa, Quartz, OpenGL and X11 on 64-bit Intel-based machines, as well as on 64-bit PowerPC machines. All non-GUI libraries and frameworks also support 64-bit applications on those platforms. The kernel, and all kernel extensions, are 32-bit only.
Mac OS X v10.4.7 and higher versions of Mac OS X v10.4 run 64-bit command-line tools using the POSIX and math libraries on 64-bit Intel-based machines, just as all versions of Mac OS X v10.4 and higher run them on 64-bit PowerPC machines. No other libraries or frameworks work with 64-bit applications in Mac OS X v10.4. The kernel, and all kernel extensions, are 32-bit only.
Mac OS X uses the universal binary format to package 32- and 64-bit versions of application and library code into a single file; the most appropriate version is automatically selected at load time. In Mac OS X 10.6, the universal binary format is also used for the kernel and for those kernel extensions that support both 32-bit and 64-bit kernels.
http://en.wikipedia.org/wiki/X86-64
Mac OS X v10.6 is the first version of Mac OS X that supports a 64-bit kernel. However, with its first release (v10.6.0), not all 64-bit computers are currently supported. The 64-bit kernel, like the 32-bit kernel, supports 32-bit applications; both kernels also support 64-bit applications. 32-bit applications have a virtual address space limit of 4 GB under either kernel.
The 64-bit kernel does not support 32-bit kernel extensions, and the 32-bit kernel does not support 64-bit kernel extensions.
Mac OS X v10.5 supports 64-bit GUI applications using Cocoa, Quartz, OpenGL and X11 on 64-bit Intel-based machines, as well as on 64-bit PowerPC machines. All non-GUI libraries and frameworks also support 64-bit applications on those platforms. The kernel, and all kernel extensions, are 32-bit only.
Mac OS X v10.4.7 and higher versions of Mac OS X v10.4 run 64-bit command-line tools using the POSIX and math libraries on 64-bit Intel-based machines, just as all versions of Mac OS X v10.4 and higher run them on 64-bit PowerPC machines. No other libraries or frameworks work with 64-bit applications in Mac OS X v10.4. The kernel, and all kernel extensions, are 32-bit only.
Mac OS X uses the universal binary format to package 32- and 64-bit versions of application and library code into a single file; the most appropriate version is automatically selected at load time. In Mac OS X 10.6, the universal binary format is also used for the kernel and for those kernel extensions that support both 32-bit and 64-bit kernels.
I've done the same; I/O stuff definitely seems snappier. I don't do any heavy-duty encoding ATM since installing SL on my new HDD, but I will be curious to see if there is any difference.
A Mac Pro with just 4GB RAM seems a little pointless. May as well be using an iMac. Unless the expandability is the priority.
2^32 bytes is 4Gb, the max a 32-bit system (Say XP) can address, and in Snow Leopard, the most a 32-bit app can address.
2^64 = 1.8^19 bytes, or 17,179,869,184 Gb..
Suffice to say we aint going to be needing 128-bit systems anytime soon 😛
As you've said, 4GB is the maximum amount of memory a 32bit system can address, but that has nothing to do with the kernel.
It doesn't make a difference if you've got a 32bit app on a 32 or 64bit kernel, the 4GB address limitation applies for both of them.
The 32bit kernel is fine for 32GB of RAM. For more the 64bit kernel becomes mandatory.
I think people are still confused with the 4GB total system memory limit of 32bit windows... 😕
How can a 32-bit kernal with a maximum address space of 2^32 bytes anymore than 4096Mb!? 😕
Good question, but how is it possible that a Mac Pro supports up to 32GB or RAM on a 32bit kernel?
That, I don't know.
However, as my computer science mate just confirmed to me, anything that is 32-bit has a maximum address of 4096Mb including HD caches, GPU memory, etc.
Well, your computer science mate is right, except for that the 32 bit kernel under Mac OS X supports PAE, which makes it 36 bit. The Mac OS X 32 bit kernel can therefore handle up to 32 gigs of RAM.