SafeSleep
Mac OS X 10.4 improved a little-known feature of Mac OS X
SafeSleep... Mac OS X 10.4 improved a little-known feature of Mac OS X; in a low-power situation the contents of memory will be saved to the hard drive and the computer will shut down.
SafeSleep lets you quickly and easily put your laptop into this sleep mode on demand. I have been using it for several months without any problems. But note that this usage of the functionality is not officially supported by Apple.