Some ppl might find this useful. I've just swapped out an X800 for an X1800XT 256meg to check its working ok, (bought for mate to upgrade his pc) . Its in the following pc:
A64 3200 (S754) @ stock
Gigabyte K8N
1gig memory @ 2-2-2-5-1t (geil ultra X)
BF2 runs (all in game option at max) 4 x AA, 16 x AF @ 1280 x 1024 and it runs at about 65-85 fps, depending whats on the screen (singleplayer). It stutters a bit but I'm 100% sure thats the 1 gig memory (REALLY needs 2 gig),
and other than that, it runs like butter, the old X800 could only run this game @ 1024 x 768 all in game options at medium and 2 X AA, 4 x AF. Based on this alone, I'd say that anyone considering and upgrade from X800/pro/XT/850XT etc to an X1800XT is gonna get a hell of an increase in performance, and most ppl here have a better cpu than an A64 3200 S754. Incidentally, the X1800XT was just installed and ran, the drivers weren't uninstalled and installed properly, so the performance might be better with a proper installation. Thats on 6.2 drivers btw.
If anyone wants some comparisons made let me know I'll see what I can do, only a limited number of games mind.