R700 multi core part explained
 

We told you before that the R600 is block architecture and that the R600 has four blocks where each had 16 Vec5 Shader units. R600 has total of 64 Shader Units divided in four blocks. The RV610 had a single block, for example with 16 Shader units, but in real life this chip has only eight. Stitching more RVC610 cores together and you will end up getting the performance of an R600.

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