Thanks for pasting the specs.....I would say that the scores are more or less OK.....the cod 5 issue u mentioned is only natural since any particle effect applied in games tend eat up more GPU power.....
when i am playing cod 5 i notice when someone is using a flamethrower or alot of things are going on it drops to about 30-40 fps
Well that's not anything unusual,mine is the same too (i have 4870X2) and the reason is as ridic said is the particle effects.
How about other games ? also what resolution do you play at ?