The new architecture will be 3d+1d instead of the old 4d+1d, the shader model will be changed to multiple operation instead of single(mimd vs simd) and the sp layout of the new hd6000 final chip will be 4d x 24 parallel processor x 20 simd = 1920sp.
%50 increase in sp count and dp/sp calculation rate increased to 1:2 instead of 1:5 is said to increase theoretical performance.
Simd architecture is also said to heal ati's current tesselation Achilles' Heel by fixing the triangle throughput being chopped in third issue. The new architecture is also said to be having flexibility for a 320 or 384 bit memory bus size.
Increased paralel processor ratio by %50 and l1-l2 caches are said to increase unit shader performance by %25-30 rate over hd5870 and that hd6000 is supposed to be %25-30 more powerful than a gtx480 while maintaining lower manufacture costs and higher chip manufacturing efficiency(%20 bigger die size than hd5870).
http://www.chw.net/2010/07/ati-radeo...e-rendimiento/ taken from chip hell.