Am I Bottlenecked by my CPU or would a GTX680 be the answer?

The 670 is currently running on newer drivers that arent available for the 680 as of yet. With these drivers the 670 is able to outperform the 680 in a couple of games. Which obviously makes no sense. To me, this means these drivers have some new Kepler optimisations that, when available for the 680, will widen the gap by a tangible ammount and get the 680 back ahead of the 670 in those few games.

On the other hand. The 4GB 670 is the same price as a 2GB 680. Dammit this is making the choice much more difficult.

I'd get the 4GB 670