ALWAYS look for the driver versions from reputable sites that are reviewing the cards. Check for the CPU they are using, dual or quad core. This can make a huge difference. ALSO what kind of games do you play, are they listed there in the reviews? Which system in the review is closest to yours. I also was confused at how these sites could have such differences in their reviews. ATI's latest driver gave them fantastic gains overall.
Remember that some games get money from the card vendors to tweak their games so they run better on their card design, especially Nvidia. That is why the synthetic benchmarks may NOT coincide with FPS in the real world until driver tweaks are made.
Dailytech had a huge list of reviews of the 3870x2 they put out on Monday , have you seen it and looked at more that just those listed above? Check it out here.
http://www.dailytech.com/1282008+Daily+Hardware+Reviews++Radeon+HD+3870+X2+Edition/article10500.htm
There is a huge number of variables in PC's check to see which testbed is more like yours(granted these are usually very high end systems) or what you will have in the near future and go by that. There is one site that used the most common (computer)setup so that they could give more realworld type benchmarks but I can not remember their name.
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