To overclock today we are using the latest beta version of Sapphire's TriXX tool which arrived with us a day before this article was due for publication. V4.6.2.
There is certainly plenty of headroom on the core as we managed to push from 1,075mhz to a whopping 1,260mhz before encountering instability or artifacting.
The manual overclock helps push the 3DMark scores from 3,735 points to 4,008 points, just shy of the HD7850 score.