Here are some more details regarding ATI's roadmap, this info was released by Dave Orton, ATI's CEO on August 17th.
The R520, RV530 and RV151 are slated slated for late September. The shipment dates will likely by staggered for the three chips, based on the delivery cycles from TSMC. Likely one will ship at launch date and the other two within the first half of October.
The highly anticipated R520 has been sampling since December 2004 and ATI claims the architecture nor the 90nm process were a problem. The reason for the delays appears to be a soft ground issue which prevented the chips from clocking fast enough. Orton says this program was discovered in July after debugging with several respins.
ATI further said the R520 and RV530 had functional yield, but the issue prevented them from running at high speeds, while the RV515 and the C1 (the 90nm Xbox 360 GPU) did not have any issues.
Performance wise ATI claims the R520 should be better than the GeForce 7800 GTX, if they can clock their chip high enough. But Orton also said NVIDIA still has some headroom to launch a higher clocked GeForce 7800 GPU.
ATI unlikely to launch its R580 (speculated to have 32 pixel pipelines) in C2005 and expect a refresh of the R500 family beginning in spring 2006 with RV560, followed by RV540 and RV505.
And the R600 with DirectX 10, Windows Vista and WGF 2.0 compatibility appears to be slated for the fourth quarter of 2006 or the first quarter of 2007.