We have 3 Macs and a PC feeding off a new Airport Extreme. Two of the Macs are new MacBooks with "N" cards. One Mac is an iBookG4 with a "G" card The PC is a Dell desktop running Win2KPro and a Belkin "G" card Question - I've been told the Extreme reverts to the "lowest common denominator" of the computers it's communicating with - and that since we have 2 "G" cards installed, we aren't getting the full benefit of the "N" speed and range on the new MacBooks. Is this true? If so, is there an "N" card available for the iBook G4? I know I can buy one for the PC.