Xion basically made the best point in the whole thread. Bar graph FPS reports don't tell the whole story. I added who cares about what your reported averages and mins are on a bar graph if the game stops for a full count of one or possibly more far too often. Look below.
That's overclocked triple HD 5870 Crossfire X results for STALKER CoP maxed @ 1920x1200. No mins below 35, averages that are sometimes above 95. Boss, right? Wrong. Hitch, hitch, hitch.
Again, turning AA off or dropping res to 1440x900 would magically smooth it out. Box was selected in the CCC and I set AA with the application.