I think AMD did a good job with cayman and barts and puts them in a position to really brake Nvidia...talking about price...

performance wise, AMD can slap to 6870 and call it 6990 and is game over for the gtx580, we know 6870 crossfire consumes less in idle and load compared to the 580, or slap two 6950 and powertuned them ...or slap together something between the 6870 and 6950(something between 1120sp and 1408sp) ...any of those 3 positions is game over for Nvidia...
thats AMD strategy since the 4000 series...always the top range card is a dual gpu...

Nvidia did a good job with the 500 series and caught AMD off guard...but AMD has the solution for it...
either way is good for us(consumer) , better prices from both sides