This is really a very interesting article and is something people need to be taking note of. The first thing you need to be checking is if you're reading a review where Crossfire is being tested. Make sure that the board there using is a x16 / x16 motherboard. The results really do speak for themselves and it’s clear that there is a performance difference between a x16 / x16 configuration which the X48 offers, and the x8/x8 one on the P45.
If you’re really thinking about going down the Crossfire path, we would be highly recommending that you spend the extra money to go to an X38 or X48 based motherboard over the P45. Of course, if you’re not then it doesn’t really matter. With one card the P45 runs at x16, which is exactly what you want.