The new power supply for my G4 (mirrored drive) arrived last week and I finally got around to putting it in today. I'm amazed at the difference! As a matter of fact I'm a little worried that I didn't install it right, and that the fan isn't running (however, I can feel air moving out the back where the main fan is, so I'm not going to obsess over it). If I'd been a little more industrious I would have recorded before and after so my faithful readers (who care about Mac stuff) could hear the difference. But I'm not all that industrious -- actually I'm surprised I did the install so soon. Anyway, if any of you are holding off on the upgrade/correction, it's highly recommended, and worth the 20 bucks, and hour's worth of labor (I'm slow)!