I saw a classified ad today for a 533MHz G4 PowerMac. I called the guy and he said it is a single processor and has never been upgraded. This confused me because I didn't think there ever was a single processor 533MHz PowerMac, I thought it only existed as a dual. Am I wrong or is the guy an idiot? ps. I am wondering because if it is a dual, I want to buy it, but if it is a single proc, I would want to pay less than he is asking.