I see a lot of GeForce cards that match the description, could you provide the exact model number? Here are some stats on the ATI though, from newegg.
Memory Clock: 1000 MHz
256MB DDR3 memory
DX9, OpenGL 2.0 support
500MHz Core Clock
The X800 also has a built in TV tuner, if that is of any interest to you. If you provide me the manufacturer or the model number of your GF card, I can look up some specs for that too.
I am in a bind, i just ordered a Geforce 6800GS $228 CDN and now I see a All-in-Wonder X800XL for $170. Should I return my card and get the X800XL, or is the 6800GS a better buy even at the higher price???