RV670XT is Radeon HD 2950XT
We got our hands on what looks like the final specification of RV670XT card. This one will run at impressive 825MHz engine and 2400MHz memory. It has 320 Stream processors just as much as R600 but it is limited with 256bit memory controller.

It is a DirectX 10.1, PCIe 2.0 card with Shader model 4.1 support made in 55 nanometre. This will be the first graphic chip ever to be developed in 55 nanometre.

The Radeon HD 2950XT card will use GDDR4 only while the 2950PRO will end up with GDDR3 at some modest speed.
Fudzilla