Hmm, depending on what resolution you play on, it will make a difference.
Let's put it this way. The X1800XT does 23 FPS on all high settings with shadows at 1600x1200.
The X800XL doesn't even come close.
I don't know exactly where the X800XL will stand, but it would probably be on the bottom.
F.E.A.R. is one demanding game, my friend.