HT3773: OS X: Starting up with the 32-bit or 64-bit kernelLearn about OS X: Starting up with the 32-bit or 64-bit kernel
Currently Being ModeratedOct 15, 2012 1:58 PM (in response to shivaparasram)
You can boot the computer and after the chime press and hold down the 6 and 4 keys together until the spinning gear appears. This should put the computer in the 64-bit kernel. You can make the change permanent by using a utility such as 32- or 64-bit Kernel Startup Mode Selector 1.6.
Currently Being ModeratedOct 15, 2012 1:59 PM (in response to Allan Eckert)
The '09 Mac Pro doesn't boot automatically into 64-bit kernel, only the 32-bit.
These Macs use the 64-bit kernel by default in Mac OS X v10.6.
- Mac Pro (Mid 2010)
- MacBook Pro (Early 2011)
- iMac (21.5-inch and 27-inch, Mid 2011)