Yeah, but see, AGP is *better*. So say the specs, anyways.

It is for several reasons, most relating to the fact that PC manufacturers have let PCI slots on modern motherboards stagnate. If a PCI-X 133 video card existed, I am sure it could do everything an AGP version could. But the only place I have commonly seen any PCI slots beyond the ancient 32bit 33mHz slots is in servers, or high end workstations.