The reason this game takes a really good gfx card to run at high settings at 45fps its because of the AA. Check this from companyofheroes FAQ
Q. What do the Antialias settings mean?
A.
Off = no antialiasing
Low = FXAA
Medium = 150% SSAA + FXAA
High = 200% SSAA + FXAA
Q. Why is the game running so slow with Antialias at maximum, if it runs fine with AA off or low ?
A. Medium and High settings mean that the game will render at a resolution way higher than you selected and then scale that down to show it on the screen, these modes
Require really powerful graphics cards as it could be rendering up to 4 times the amount of pixel of your selected resolution. For example, if your resolution is 1080p (1920x1080) antialiasing high means it will be rendering actually at a 3840 x 2160 resolution!
Im sure if they did the benchmark with everything in high except the AA being in low they would have much better results