Sources tell Expreview that AMD is working on a new graphics processor (apart from the mysterious RV790), as an immediate reaction to the 55nm high-end GPUs NVIDIA is set to release. NVIDIA on its part is working on GeForce GTX 260 (55nm), GeForce GTX 285 (successor to GeForce GTX 280) and the dual-GPU monstrosity, GeForce GTX 295. To rival this, according to the source, AMD is working on the RV775 and derivatives based on its yields' performance.
These GPUs are slated for January thru March 2009. It has some very interesting specifications. To begin with, 840 stream processors. While stream processors on a current generation RV770 cannot be added/subtracted in quantities of 40 stream processors, perhaps, the increment of 40 SPs is derived from an extra ALU cluster the RV770 comes with by default (which helps in die harvesting, where the spare ALU cluster makes up for any damaged cluster, thereby improving yields). This would require near-perfect GPUs in the making (if re-engineering of the RV770 on a large scale is to be avoided). Another interesting point is regarding the smaller die. At this point we are clueless as to how that is possible without re-engineering the RV770 at a large scale. Treat yourselves to the specifications meanwhile:
Source: Expreview