The reference card shown here is a big and power hungry as you can see from the 8-pin and 6-pin power connectors located above the fan. 

On the back you can see the two GPU locations on the PCB - this should be an incredibly fast graphics card.

What might be a bit concerning is the length of the card - this design was 13.5-in long and had issues fitting into this full size Antec 1200 chassis. 

AMD already got a hold of the guys who posted this so the performance numbers that were along side the photos were taken down before we got to see them.  Also, AMD told them that the HD 5970 card seen was an early engineering sample leaving hope that the final retail card will be a bit shorter.

Either way, I think we will learn more about this upcoming GPU before you know it.  Stay tuned!