As we've said before R670 is the codename for two RV670s on the same PCB. It is a product name more than a traditional chip codename. It is not a die shrink of R600, it actually means that it embraces two chips on the same board.
This product will show up in Q1 2008 and it will fight with the D8E, Nvidia's dual chip solution. This is the last product based on ATI's Rx6xx marchitecture and already in Q2 2008 ATI plans to introduce its brand new mini core marchitecture codenamed R700.
The next generation dual chip card will dissipate less than the R600, or just above 200W, and DAAMIT can thank the 55 nanometre process for that.