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j-a-x

macrumors 68000
Original poster
Apr 15, 2005
1,582
291
Houston, Texas
I've got a MacBook 5,1 13" unibody. It's supposed to be capable of booting into the 64-bit Kernel in Snow Leopard but holding down 6 and 4 on startup does not seem to do anything. It has 64-bit EFI, a 64-bit processor, no 3rd party 32-bit extensions installed, but it still will not boot into 64-bit.

Does anybody know how to boot this machine using the 64 bit kernel?
 
Apple made it so the MacBooks cannot boot the 64bit kernel...even the pre-Pro aluminum MacBooks cannot.

There's no end-user benefit to having the kernel is 64-bit mode, so no worries, all programs can still run in the 64-bit space.
 
There's really no advantage. In fact, the only thing you might notice is the fact kernel_task sucks up more memory.
 
There's really no advantage. In fact, the only thing you might notice is the fact kernel_task sucks up more memory.

There are some slight performances increasing linearly with the addition of RAM to the system above 4 GB, through the performance increases are only really noticeable when working with large quantities of RA in the Mac Pro or Xserve. It's not really worthwhile to enable the implementation of a kernel that only improves memory management on a laptop that will likely not go above ~6 GB (IIRC), and beyond that Apple has a habit of purposely taking measures like this to jive users into upgrading before they otherwise would have.
 
I read that Aperture 3 runs better with the 64-bit kernel extensions. Maybe that's not true, but I kind of wanted to try it for myself.

Holding 6 and 4 on startup doesn't do it. So there's absolutely no way? Not even a fun hacky way? I know the hardware and EFI is capable of running 64-bit. So is there something in the software blocking it?
 
I read that Aperture 3 runs better with the 64-bit kernel extensions. Maybe that's not true, but I kind of wanted to try it for myself.

Holding 6 and 4 on startup doesn't do it. So there's absolutely no way? Not even a fun hacky way? I know the hardware and EFI is capable of running 64-bit. So is there something in the software blocking it?

IIRC there is embedded code in the kernel preventing it from running on those machines, and the only fix would be a partial re-compile. I don't know that it would be worth the supposed benefits running a non-vanilla kernel on Apple hardware, as it could cause negative consequences far outweighing the original intentions.
 
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