Not sure, but it was BUILT with the design to have BOTH AGP and PCIe.
ECS has a AGP and PCIe Intel 915 chipset board, BUT have said you will lose anywhere from 5-20% of performance using the AGP port as the 915 chipset does not TRUELLY support AGP.
So it looks like VIA may have a upper hand on the next chipset when the new P4 chips come out.