Interesting to see your X850 is running well as it should be. I have not been able to get BF2 to function properly since the install of my X850 XT a month ago. I was using OmegaDrivers and it loaded BF2 but graphics would fade out to black (this is a resolve in the ATI 5.8 Catalyst - See release notes). So, unloaded the OmegaDrivers which were based on the 5.7 Catalyst, then loaded the ATI 5.8 Catalyst and BF2 crashes to the desktop right at start up. I will keep debugging. Going to do a complete nuke tonight of BF2 and re-install.
I'm having a similar problem with BF1942. It worked fine until I installed the 1.6 update. Now I can't play in widescreen without crashing to the desktop. Adding Desert Combat didn't help anything. I actually think DC is a superior game in many ways, chief of which is the helicopter contols and radar. Not having radar when flying into a fog screen 1km away is kinda lame.
One time in BF2 Demo I climbed to the top of the crane and did nothing but "spot" enemy aircraft and tanks. It made a huge difference for our Mig pilots.