That means absolutely nothing. Its a totally different game, totally different engine.
By that logic you could try to claim that Xenos is more powerful than the 8800GTS since it "only" gets ~40fps in these "much inferior graphics". How could it get 3/4 that performance in BF:BC?
Do you think Xenos is more powerful than the 8800GTS?
Another example: the 360 has framerate problems in Oblivion, does that mean Oblivion is the best you can get out of the system?
No, its not, no more so than R6:Vegas is the best you can get out of a 1950XTX.