Well, I just finished replacing the DVD burner (Pioneer 112d) in my iMac G4 1ghz 17". Talk about a change from the previous one. Its so much faster. I also changed out the 200pin 256mb internal ram with 1gb crucial memory. I can already notice the improvements and I'm running CS2, firefox, iTunes, Messenger, and active monitor and there still are no page outs. I also put the thermal paste on it once I was done. All in all it was well worth the upgrade. It was $100 total for the DVD burner, 1gb memory, arctic silver 5 thermal paste and shipping from newegg. And yes you can have more than 1 gig in the iMac 1gh or 1.25ghz model. I'll maybe upgrade to 2 gig later in the sodimm slot.