Snow Leopard System Mode Configurator Preference Pane - 32/64 bit boot selector

SystemModeConfigurator is a system preference pane application which can switch Your Mac kernel boot mode to 32/64 bit (it uses nvram boot-args). On systems other than Snow Leopard it only displays Your system capabilities to run 64bit kernel. It also can turn on verbose boot/shutdown kernel mode - now You can see what happens during boot time and You can impress Your geeky Linux friends ;-)

It is important to know that there are no good reasons to run machines with less than 4 GB RAM in 64 bit mode. Snow Leopard runs 32/64it applications in both modes (look at Activity Monitor application). The only real differnce is that 32 bit mode cannot run 64 bit kernel extensions and vice versa (so VirtualBox and Parallels Desktop may not run in 64bit mode). Feel free to experiment with 64 bit technology.


Version 1.1

Only machines with 64 bit EFI and machines that Apple offcially claims that are compatible can boot 64 bit.

Snow Leopard 64bit compatible machines:

After download/unpacking click on SystemModeConfigurator.prefPane file in Finder. It will be installed in Your System Preferences:
System Mode Preference Pane - v1.0

If everything goes well You should see SystemModeConfigurator panel and System Mode icon at the bottom of the System Preferences main screen.

To uninstall this preference pane from System Preferences use secondary click (right click) on its icon and remove it

Here is an example of running System Mode Configurator on 10.6.1 MacBook Pro (early 2008):
System Mode Tab Pane - MacBookPro 10.6.1 - v1.1 Advanced Tab - v1.1

Here is an example of running System Mode Configurator v.1.0 on 10.5.x Mac Mini:
System Mode Preference Pane on Mac Mini 10.5.x - v1.0

If You notice any undesired behaviour please leave comment at the bottom of this page or mail me.

Version 1.1

  • runs on Intel Macs (10.5.x or later)
  • change boot mode to 64bit/32bit on Snow Leopard
  • check Your EFI type on Leopard/Snow Leopard

Change history:

1.1 - 2009.09.23
  • now it uses more standard way to authenticate admin operation in System Preferences
  • it is possible to turn on verbose mode to impress Your Linux Geek friends :-)
  • shows boot parameters in advanced tab

1.0 - 2009.09.13
  • initial public version

(C) 2009 Copyright by IGI-SOFT Igor Popik. This software is freeware. Full license text is available here.