I've been scouring this forum trying to find peoples inputs on the next-gen graphics that the iMac (and quite possible, the next-gen MacBook Pros) will incorporate. As of now, the big-boy is the 6970m with 2GB of GDDR3. Perhaps the next card will be the 7970m? I'd like to know some peoples speculations - as well if this is a worthy upgrade in performance. (I've heard talk of a 50% increase in speed...or something like that...) What about the possibility of crossfiring two 6990m's? Would there be too much heat? Let me know what you think! Cheers.