The best way I have found to overclock ATI AGP cards on modern-ish mobos is RivaTuner. You have to do a registry hack to use RivaTuner in Vista64, however, because it uses an unsigned driver. It works, though. Really well, actually, I overclock my AGP X1650 from 500mhz to 600mhz no problem. No amount of overclock will help that card's shader performance, however. It has 12 of one type and 8 of another. Not unified. And only 256mb of DDR2. My current plan is to upgrade to a PCIe board and get a nVidia 9600gt. That should really help, I think. Not so much from the bus bandwidth as the shaders and video ram and general architectural improvements.