I’m hard-nosed about it: If it’s not 64-bit, it’s gone.

Hmmm… I found a few old 32-bit extensions via the System profiler. The Kensington Mouseworks extensions are all 32-bit and, as disappointing as it may be, I’m betting that Kensington will not be updating it to 64-bit. Even the drivers for their latest SlimBlade trackball have not been updated since 2007.

I tried restarting and holding down the 6 and 4 keys, and that didn’t boot me into 64-bit kernel mode. Shutting down and then cold-booting, while holding down the 6 and 4 keys, didn’t work. I wonder why my Mac Pro won’t boot into 64-bit kernel mode. The only 32-bit extensions I have left are BSDKernel6.0, IOKit6.0, Libkern6.0, Mach6.0, and System6.0. So, what’s preventing me from booting into 64-bit kernel mode?

Very helpful. Thank you.

Thanks John M. I’ve actually found the answer to my own question. It appears that only Macs with 64-bit EFI can boot Mac OS X 10.6 in ‘64-bit mode’.

Easy way to tell if your Mac has 32-bit or 64-bit EFI, is to run the following command in the terminal:
ioreg -l -p IODeviceTree | grep firmware-abi

(BTW: that first switch is a lower-case L, not a 1.)

Unfortunately, on my Mac, the answer to that command is “firmware-abi” = <“EFI32”>, so no 64-bit kernel for me! Maybe once enough time has passed for most devs to update their drivers/extensions to 64-bit, Apple will update Mac OS X 10.6.x to allow it to boot with a 64-bit kernel on a 32-bit
EFI. Or, maybe we can hope that they’ll put out 64-bit EFI/firmware updates for those Macs that currently have 32-bit EFI could run a 64-bit EFI. I know my Mac Pro1,1 is hungry for 64-bit EFI!

Glad to know this, I had been hitting myself for not picking up one of the older Xeons on refurbish - this could have issues down the line. Also means that some of my hardware may need to be updated later.

Still waiting on FW3200 - I believe this is why all Macs now have 800 as it is supposed to be compatible. Therefore all Macs have FW3200 waiting for product !

by the way, please change word to word and number

Easy way to tell if your Mac has 32-bit or 64-bit EFI, is to run the following command in the terminal:
ioreg -l -p IODeviceTree | grep firmware-abi

I ran this on my MacBook Pro and I got <“EFI64”>.  I still can’t boot into 64bit mode by holding down the 6+4 keys at startup.

I ran this on my MacBook Pro and I got <“EFI64”>.  I still can’t boot into 64bit mode by holding down the 6+4 keys at startup.

Sorry about that. From other information I’ve more recently read, there are actually only a selection of models that support booting into 64-bit mode.

Here’s a link to the article with the information:

http://www.osnews.com/story/22009/Snow_Leopard_Seeds_Use_32bit_Kernel_Drivers_by_Default

Thanks for the info.  It looks as if my MBP may be enabled some time in the future because it has one of the “artificial” limitations even though it has EFI64.

I tried the 6+4, on my MacBook Pro 4.1 and the system booted into 64bit.
Not sure if there is perceivable difference.  Why would I want to run this way?  I can already see my full 4GB of ram in 32Bit.

Can anyone enlighten me?

This is a great idea to see what people need to update before their systems are completely ready for a 64bit kernal im one down with litle snitch. next up soundflower

I’ve boot Snow Leopard in the 64 Bit Kernel mode, and the 32 Bit Applications STILL work.  What is the fear of most users using 64 bit kernel boot up if that is so?  Is it because some EXTENSIONS are not 64 bit (most of those seem like for older systems anyways) but that APPLICATIONS in 64 bit mode would still work even if the application is still only in 32 bit mode?

It may be on obsession, John, but this is definitely NOT what Apple promised.

Here’s why some of you can’t boot the 64-bit kernel:

Although the new MacBook line no longer uses the X3100, Mac OS X 10.5 (Leopard) ships with drivers supporting it that require no modifications to the kext file. Mac OS X 10.6 (Snow Leopard), which includes a new 64-bit kernel in addition to the 32-bit one, does not include 64-bit X3100 drivers. This means that although the MacBooks with the X3100 have 64-bit capable processors and EFI, Mac OS X must load the 32-bit kernel to support the 32-bit X3100 drivers.

Source: Wikipedia
http://en.wikipedia.org/wiki/Intel_GMA#Mac_OS_X

PS. I also want to run my kernel in 64 bit mode. It doesn’t matter why, my Macbook is capable of doing it and I’ll be VERY upset if it doesn’t JUST BECAUSE APPLE DIDN’T BOTHER TO RELEASE THE APPROPRIATE DRIVERS FOR A COMPUTER THAT IS NEARLY ONE YEAR OLD.

Yep, none of my 3 recent 64 bit EFI macs will boot in 64 bit mode, and it seems that the reason is that the actual Snow Leopard installer selectively loads the 64 bit extensions into a list of macs of Apple’s choosing absent of a known technical reason. So no 64 bit kernel here regardless of the compatibility.

I feel like I was hoodwinked.