All you need to remember is that if it has Firewire 800, it will NOT boot OS 9. And Classic mode is NOT usable to run Pro Tools 5.x on. The really confusing thing is that there are 2 versions of the Dual 1.25, one that boots OS9 (regular FW400), and one that only boots OSX (FW800). The current one you can buy new from Apple WILL boot OS9, but before the G5s were announced they did sell a line-up of Powermac G4s that did NOT boot OS9, and those were a single 1 GHz, a dual 1.25, and a dual 1.42. Confusing, isn't it?