the limitation applies only to the built in IDE interface of the B+W g3..
as a current B+W g3 450mhz owner, i can say that is the reason why i have an Acard 6880M installed in mine
installing any type of pci storage controller will sidestep the issue completely, 100%
but the g3 b+w can definately be more buggy then the g4's that followed it..
even when using a pci storage controller, sometimes u need to do a pram reset
i think it is to do with the openfirmware implementation? im not sure.. but it usualy
takes more tinkering then the AGP g4's.