After checking out the COD performance review at Firing Squad I noticed the Radeon cards are all capped at 89 FPS or so. He describes this as a situation of CPU limited performance which would make sense, however, in the new NV performance review the cards there are all performing way beyond the 89 FPS we see in the ATI article.
I also noticed an update note saying they had "accidentally" run the ATI cards with a max_fps value of 85 and that the article now reflects the corrected values. (Pretty irresponsible IMO especially considering that this is basically a quake engine game.)
I am still seeing the ceiling effect in the chart....