Take it with a grain of salt, but one of the first 3DMark Vantage scores of what is claimed to be ATI's forthcoming Radeon HD 6870 were published on a Chinese forum. The included GPU-Z screenshot indicates the card has a 850MHz core clockspeed, 256-bit memory bus and an unidentified amount of GDDR5 memory clocked at 6400MHz (effective).
A forum member on Chinese website has leaked a 3D Mark Vantage Extreme benchmark, alongwith a GPU-Z screenshot, alleged to be from a next-gen ATI Radeon HD 6870. The important result is the 3D Mark Vantage score, which X11963. Considering the GTX 480 offers under X10000, and the HD 5870 is in the X9000 range, this is an impressive result for what is rumoured to be a minor intermediate generation on the same 40nm process.