Works great on my G4 and my Powerbook. The Documentation is great. Does not on my PowerMac 8100. I sent a note to Tech Support, not expecting much since this is freeware. I was absolutely amazed to receive an answer from "Jason" informing me that since my 8100 is NuBus based, the Super Res won't work with it. I'm impressed with the quality of the support, in addition to the quality of the product.