The system requirements for hosting a 4-way video chat in iChat AV 3 say "Dual 1 GHz G4 or faster, any G5". Does this mean: -Only dual-CPU G4s are beefy enough? -No PowerBook, even the ones Apple sells today, is good enough? If that's the case, then none of the Macs in my family are powerful enough for the task. That would be a shame, since this is one of the Tiger features I was most looking forward to.