The x1300 was the low range replacement for the x300 that was in the same generation as the x800. at the best it performs somewhat similar as a x600. The Vanilla 6800 has performance on level with 7600GS. There is no question about it the 6800 card is the better out of the two.
Gforce cards came with shaders 3.0 in the 6xxx generation ATI cards a generation later with the X1xxx cards.