halifax1

The latest version of Apple's Mac OS X "Snow Leopard" will be released on August 28th, 2009. Those of us who will be upgrading, or are using build 10A432, which is the "Golden Master", may realize that by default, 64-bit kernel and extensions is not enabled.

If you are running Snow Leopard, or when you do run Snow Leopard, you will notice on all machines except for XServe machines, that 64-bit kernel and extensions will look like this in System Profiler:



As you can see, 64-bit Kernel and Extensions is currently saying No.

Also, you may know that you can enable 64-bit Kernel on some (capable) machines by holding the "6" and "4" keys at boot. This will only work on (capable) machines, and those machines must have a 64-bit EFI.

To check which EFI version you have, type this into Terminal:

And you will see either "EFI32" or "EFI64" returned to you.

If you have "EFI32" returned, you cannot enable 64-bit Kernel and Extensions, but you are still able to run 64-bit Applications.

Now, you can either continue to hold "6" and "4" everytime you want to boot, or you can do the following:

Navigate to the following location in Finder:

From there, find this bit of text:

And add arch=x86_64 between the <string> tags, so that you have this:

Save the file, and reboot your machine. If you have a (capable) Mac, you will see "Yes" in System Profiler, instead of "No".

If you want to boot into 32-bit, just hold "3" and "2" at boot, or edit the file again, and remove that string.

Hopefully this helps some of us with a Mac and Snow Leopard.

Cheers!

Edit: I have realized, that in System Profiler, it may still display "No".

You can check if you are running 64-bit by default, by checking Activity Monitor, and next to each process, if it's enabled as 64-bit, it will say "Intel (64-bit)".

This would not be displayed if you were not running the 64-bit kernel, to my knowledge.

You can also view it in System Profiler by clicking "Extensions", which will display most, if not all, of them as 64-bit enabled.



The above shot, shows the Extensions pane, and at the bottom of it, it says "Architectures", and states the x64 kernel being loaded. Also, to the right of all of them (almost), it says 64-bit (Intel), and says YES next to them.

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Vostro

YOU ROCK!!! Im going to try this right now! +Rep

EDIT - OK Im getting the error-"The document “com.apple.Boot.plist” could not be saved." Going to reboot and try again
EDIT 2 - OK its still not letting me save the file. I just took over ownership of the file so I have no idea what I am doing wrong.
EDIT 3 - Got it! Awesome tips and thanks so much!

halifax1

Make sure to check out my edit, as mine still states as "No", but if I boot in Verbose Mode (Command+V), the first piece of dialog states the kernel I've stated to run, as well as "64-bit Enabled" near the first bit of text, so it is indeed running the 64-bit kernel and extensions.

I'll update the OP with a few more shots showing it.

Thanks to you to remind me about holding 6 and 4, I decided to figure out how to default for it!

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OrphanShadow

This will be handy to know for when my update arrives

Just out of curiosity, what benefits are there to running the 64-bit kernel? Will it kill 32-bit compatibility? Any performance benefits?

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halifax1

Running 64-bit still runs all 32-bit programs.

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The Hundred Gunner

Darn, a Macbook [2,1] only has a 32-bit EFI.

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"I just talk the way I see things... If that's offensive to you... I'm sorry; you're a loser." - Michael Savage

"But you would be amazed by how many people think that the only reason to have a computer is to play games, and that playing games is all that anyone with a computer does." - dangerousHobo

Dawlish7

There is my answer aswell sigh

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Dawlish7, El Gappo, King_play334.

Vostro

From what I read I believe they will still work you just have to wait until Apple officially enables the 64bit kernel

The Hundred Gunner

My mac needs a new motherboard anyway. Maybe in a year or two I'll an upgraded board up and be able to use the 64-bit kernel that way.

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"I just talk the way I see things... If that's offensive to you... I'm sorry; you're a loser." - Michael Savage

"But you would be amazed by how many people think that the only reason to have a computer is to play games, and that playing games is all that anyone with a computer does." - dangerousHobo

aircub

Worked fine for me