I have an old G4 mirror-door that I use as my PVR. It's stuffed with 4 big drives to record media, but it runs all day and sucks tons of power. Plus, it heats up the cabinet like an oven. Is there a piece of software etc. that can help the mac better manage its power consumption? I don't like using the OS X drive sleep option because the drives always go to sleep just when you need them..