At this point if possible I'd suggest waiting for the good ol R520 and then buy.

(Although admittedly I'm quite pleased with my 7800. At 1680x1050 w/ 2AA, all settings on Ultra_high except Dynamic Light and Shadows, and Multisampling Transparency AA, I typically hit BF2's FPS cap of 99.9 in multiplayer, and generally stay there most of the game. (Some drops down to 70,80 etc, depends also on server lag.)
Anyway, that's how the 7800 should perform IMO. 100+FPS on high res with high detail for a fairly reasonably optimized game. No idea what I get in FEAR but don't consider that a valid test because of its crap code.