while the blue and white g3 does have the faster bus and bigger HD capacity it does not come quartz extreme ready, i own one myself (just got it last year) and while the card in it has 16 megs of ram it is on a pci bus (no agp slots here) and is a rage pro 128, you need at least a radeon or geforce on an agp bus to use QE. however you can buy a pci radeon and use a hack to push quartz onto the pci bus rather then the non exsistant agp bus. aside from that these machines can be upgraded to 900mhz g3, 800mhz g4 or 1ghz g4 as well as a gig of ram max, i own one at g4 450/448mb ram/50gb hard drive storage and it works great, i use it to do all my graphics stuff (student in training!) but it all depends on what you want to do, if your not gonna do lots of altivec intensive stuff pick up the 900mhz g3 upgrade and about half a gig of ram and a blue and white would run quite nicely.