Force Snow Leopard to Use 64 Bit Kernel
By default, Mac OS X Snow Leopard boots using a 32 bit kernel. But did you know you can switch between the 64-bit kernel and 32-bit kernel upon boot?
This should be useful to advanced users who may need to perform such a feet, though the average Mac use likely has no business forcing one kernel to load over another.
So, let’s cover how to do it:
You can force Snow Leopard 10.6 to use the 64 bit kernel by holding down the “6” and “4” keys during system boot.
Likewise, you can switch back to the 32 bit kernel by holding down “3” and “2” during system boot.
It may be stating the obvious, but the 64 bit kernel will not work on a machine that is not 64 bit.
You can verify the 64 bit kernel by typing the following at the Terminal:
Note: some users suggest this only works in the Mac OS X Server edition, though I am unable to test this specifically. Share your experiences in the comments.