The theoretical max performance of a fully populated card is 128 GH/s. It's highly unlikely that we'll ever get close to that peak performance. Nevertheless, there's quite a bit of margin left above the 60 GH/s mark... some of which is being enjoyed in the Mini Rig configuration of the card.
So the actual max is not 1Ghz but closer to 1.1Ghz.
With a max draw per chip of about 16 watts.