This preferencepane will enable you to switch between different sleep states on your mac
sleep
hibernate & sleep
hibernate
If you own and PPC Mac with 1GHz or more chances are good that Hibernation will work on your machine. Some machines do need the NVRam patch. That means that there are some values then stored in the no-volatile ram of the computer to say it's hibernate capable. When the os boots up it checks for those values. The software currently tests for machines>=1 GHz to enable NV-Ram patching. It is known that some machines don't sleep at all, some won't start up their fans when hibernation is enabled. In case something goes wrong disable hibernation by resetting the NV-Ram (Hold down CMD-ALT-P-R when booting).
In any case use this software at own risk. There might be a reason why apple enables hibernation only on newer machines.
Full Specifications
What's new in version 1.00
now works on Intel Macs as well, where you can now have the sleep option with out hibernation for fast sleep now.
General
ReleaseAugust 26, 2008
Date AddedSeptember 17, 2007
Version1.00
Operating Systems
Operating SystemsMacintosh, Mac OS X 10.4 PPC, Mac OS X 10.4 Intel