Due to the 4870x2 having a bridge chip that provies 160 GB/s of bandwidth, it is entirely possible, which likely means r700 will act as an mcm if that is the case (now I did not say will be an mcm, act as an mcm, probably too much concentrated heat if it was an mcm). But there's no guarantees yet, but due to the huge delay between the 4870 and 4870x2, likely something big is changed in the r700 from the r680