We've had my wife's G4-AGP Sawtooth/500 forever (or, at least since they were the hottest G4 available) and I recently found a place to get original Apple Dual G4/500 modules for a little over $100. I got one, bought the heatsink from an Apple dealer for $28 and we've got a much better performing machine that will last us a bit longer -- at least until the 3Ghz G5s start shipping. The most notable improvement of dual over single processors is in tasks like Photoshop rendering and all sorts of printing and scanning tasks. Huge performance increase realized. Email me directly if you'd like the info on the place I got the Dual G4/500 module. Regards, Jim