32- or 64-bit Kernel Startup Mode Selector 1.2.3

32- or 64-bit Kernel Startup Mode Selector… Mac OS X 10.6 Snow Leopard is 64-bit – or is it?

Well, actually Mac OS X 10.6 Snow Leopard is both 32-bit and 64-bit, and what that means for you depends on both your hardware and your settings.

I put up an accompanying website which should answer most of your questions
here.

What does this app do?

it shows whether you have a 32-bit or a 64-bit processor
it shows whether you have a 32-bit or a 64-bit EFI
it shows whether the MacOS X Kernel is set to boot in 32-bit or in 64-bit mode
it shows whether the MacOS X Kernel is running in 32-bit or in 64-bit mode
it shows whether Apple officially supports booting a 64-bit kernel on your Mac
it allows you to select whether you want to start the MacOS X Kernel in 32-bit or in 64-bit mode (the setting might be ignored on MacBooks, depending on how Apple implements the restriction)
accompanying webpage explains what the whole commotion about 32-bit and 64-bit in MacOS X Snow Leopard is about

Requirements:

To check your configuration:

To set the kernel’s startup mode:

WHAT’S NEW

Version 1.2.3:

Change: the ability to set the boot mode was disabled again for earlier MacOS versions as changes to the kernel boot mode only effect MacOS X 10.6.

REQUIREMENTS

To check your configuration:

To set the kernel’s startup mode:

32- or 64-bit Kernel Startup Mode Selector 1.2.3 – Check your system & set the kernel startup mode.