iirc, nVidia generally does a little better in BF3, but I have not seen what difference the latest AMD drivers made.
Also, do note the results of those FCAT tests. For now, Crossfire is a waste. FRAPS numbers will be much higher, but what a gamer actually sees will be the same as (or worse than) what a single card can produce. It has to do with a large number of what the articles call "runt" frames. Read them, they're really very interesting.