I have a Dual 1.25 GHz Mirrored Drive Door G4 and something strange is going on with the Firewire. I was having trouble with a Firewire drive on this computer yet the drive did not show any hint of a problem when used with my slower 400 MHz Sawtooth G4. Both computers were running OS 10.3.5. Since the Dual was under warrantee I even had the Firewire card replaced. I am still having trouble with the Dual 1.25 and the Firewire drive. The Apple Authorized repairman said there was still an instability when the Firewire drive is connected but the problem was too intermittent to tracdk down. He recommended replacing the firewire drive. Since I don't have two Dual 1.25 computers, I cannot test the drive on another similar computer. I can only test it on a slower one. I have never had a problem with the Firewire drive and the slower G4. What brands of Firewire drives do people with Dual 1.25 Mirrored Drive Door have and like? Has anyone encountered such a problem. The Firewire drive I have is an OWC Mercury Elite, 250 GB. 7200 RPM. Carol -