i still think your expecting something out of hardware that just isn't what you think it is. the 6800 series is now two generations old with the 8800 out. granted they are (8800's) way overpowered for any game atm, the 7800's were more then twice as powerful as a 6800, and its likely that a 8800's will be more then twice the power of a 7800, its even likely that it has more raw power then quad SLI. thats how it works. fear never ran well on my brothers 6800, idk what your expecting out of such an old card. and your CPU is definitely holding you back. i was "testing" my brothers 7900GS while his new PCIE motherboard was still in shipping, and the difference between my athlon64 @ 2.8ghz compared to his still at 1.8 were beyond words. even at stock speeds at 2.2 it hammers his comp. and a i can barely tell the difference (on his comp) in games, between his old 6800 and his new 7900GS. dual cores still aren't necessary, but for games like fear and half life 2 a good proc is still a must. and any socket A wont take the heat even compared to older procs like mine, much less conroes or X2's.
not trying to sound harsh or put you down. but you seem grossly misinformed, if your getting 50 FPS in fear all settings maxed on a 6800 i personally wouldn't complain. that basically qualifies as positive e-penis points