I am torn by the material I am seeing coming out on this. What I mean is, and PcPer actually said this, a lot of this data gives an impression of a certain result but in the real world holds little meaning. The "stutter" that seems to be the root of this data is something that is highly subjective to the viewer when it comes to how the game plays. The question I keep asking people is, if you did not have this data would you have been worried, concerned or upset about your quality of game play and the majority say no. The reason is, a stutter that cannot be perceived is not meaningful.
Also I would take any testing methodology provided by one of the two GPU makers with a grain of salt. Both have a history of fudging data in a way that makes the other look worse than they are. When we see an independent company produce a testing methodology then I am more willing to consider the results.
Now as I have said I am torn on this and the reason why is I have been a huge advocate over the years that the so called average frame rate was not as meaningful as massive dips in the frame rate during play, that consistency is much more important than high numbers. This material, if taken at face value does show that AMD has an issue with Crossfire, something BTW that most gamers already knew. However it is being attributed by way to many people to way to many other issues.
My concern is that at the end of the day, without a third dis-interested party actually providing the methodology, we could very well see a big witch hunt going on right now. And just as happened in Salem the accused have no counter because how do you counter evidence that has no other way to be shown but the word (and methodology) offered by the accuser.