AGP 4x. Really old systems won't gain performance because of the CPU/RAM being the bottleneck, but they also don't have AGP 4x.
Abit IS7 @ 275 FSB, VAGP @ 1.65, OCZ PC4200 RAM @ 550Mhz, P4 2.4 @ 3.3Ghz Vcore @ 1.625, GeXCube Radeon 9600P @ 450/626.
Thermalright SLK-947U, P3 HS @ NB.