Would an AGP DDR2 fit on a regular AGP slot?

The memory (DDR2) doesn't make a difference for compatibility. What you should check is to make sure that the motherboard takes 8 x AGP. Some really old motherboards might use an older form of AGP that may or may not work with this contemporary AGP card. That PC is pretty recent, so it's almost certainly an 8X AGP. The one problem I can foresee is maybe needing to shut off the onboard video controller. See a href="http://en.wikipedia.org/wiki/Accelerated_Graphics_Port" rel="nofollow"http://en.wikipedia.org/wiki/Accelerated…/a