http://www.anandtech.com/show/5699/nvidia-geforce-gtx-680-review/17
or if you dont believe that, then just google some more benches and tests.
Anyways, don't get offtopic please
I was going to suggest he does his own homework, as it's not right for any of us to do it for him.
There are many benchmarks in which 680 appears faster, but in actuality once you move into a real world and forget synthetic tests, the picture is totally different.
For example Adobe CS applications, Apple Motion and Final Cut Pro, DaVinci Resolve, etc. Then in the 3D land, most content creation packages perform better with older generations of NVidia chips such as 5xx, 4xx etc. They are closer to their equivalent Quadro chips and could potentially be modded to Quadro as well.
With 6xx, NVidia has clearly decided to separate gaming from business applications. They really want you to spend the big bucks on their pro-line (Quadro) for anything "serious" and so modding the 6xx will only take you so far. As I said before, they are not sitting idly either, waiting for modders to make their moves.
What's mind boggling is that it appears both 6xx and Quadro Kxxx chips come from the same factory line and the former are just crippled versions of the later; or those that don't pass QA testing for pro-line. But, we've already discussed that here, in the earlier posts...