To overclock today we are using the excellent Sapphire TriXX software tool. Catalyst Control Center is limited to specific speeds.
We managed to get a whopping 205mhz out of the core before artifacting would occur. We also were able to squeeze another 102mhz from the memory, achieving a final effective GDDR5 figure of 4808mhz.
The hefty overclock pushes this card to the top of the performance chart, adding 2796 points to the final score. At these settings, temperatures rose by 5c, which are incidentally still lower than the reference card.