XSReviews has reviewed the Sapphire 4870 x2 graphics card
A quote from the article:
>> Sapphire 4870 x2 Review
Although practically every other review site has beaten us to it, it's still always a bit exciting to receive the world's most powerful graphics card at the time. We recently we had nVidia's top end offering, and this week Sapphire have been kind enough to let us take a look at theirs. This card is called the 4870 X2, and as the name implies it's 2 x 4870 GPUs on one card. It's absolutely monstrous, but does it perform as well as everyone's saying? Let's see if XSR concurs.
>> Sapphire 4870 x2 Review