To overclock the XFX HD6970 Black Edition today we used the excellent Sapphire TriXX software.
Our overclocking results were very good, getting the core stable at 1005mhz with the memory running at an effective 6420mhz. Temperatures rose by another 3c however, peaking at 97c under full load. We would certainly generate our own fan profiles to use this card in an overclocked state.
The substantial overclock helped to generate almost 3 extra frames per second with the intensive Unigine engine.