if you're talking 'bout the GeForce 256, it's gonna be a power supply problem. both of them are huge power suckers...make sure you have a 300watt PSU at least..other than that, there's no compabitiliby problem...
install OS, reboot
install VIA 4-in-1, reboot
install vid card drivers, reboot
install peripherals and drivers, reboot
that works well and that's to make sure you don't have any driver problems...
cheers!