We got our hands on what looks like the final specificationd of the RV670XT card. This one will run at an impressive 825MHz for the engine and 2,400MHz for the memory. It has 320 Stream processors just as many as the R600, but it's limited by the 256-bit memory controller.
It is a DirectX 10.1, PCIe 2.0 card with Shader model 4.1 support and it's a 55 nanometre design. This will be the first graphics chip ever to be produced at 55 nanometre.
The Radeon HD 2950XT card will only use GDDR4 memory, while the 2950PRO will end up with GDDR3 at some modest speed. This GPU is planned for introduction in November and ATI's partners are really excited about it.