The reason I am asking is that I believe the 780 could do nearly double of what a 660Ti does. 350-400kHash/s I believe. It has twice the memory bus width (and hence bandwidth) and it has 2304 shaders compared to the 1344 shaders in the 660 Ti. I woud just like to have a confirmation of its hashing power before I shell out 400 Euros for one .  Also it has Compute 3.5 capability, and I think this would allow for some extra code optimization in the future.

This is what's in my development box currently

580Ti                       (150 kHash) - Compute 2.1
660Ti                       (200 kHash) - Compute 3.0
580Ti 448 core edition (220 kHash) - Compute 2.0
GT 640 (GF 208 based) (55 kHash) - Compute 3.5

That's a pretty good variety of compute capabilites, so I can optimize for different generations of hardware.
When everything crunches simultaneously, the machine pulls 800 Watts from the power socket.