ATI's R600 is still on schedule for a Q4 2006 launch, The Inq claims.
Nvidia will be the first to launch, with its G80 chip, while ATI will have a refreshed R580+ powered with GDDR4 to counter Nvidia's new offering until its new beast arrives.
ATI is using the dust-it-out strategy but I don’t think it has any other choice as it cannot push delivery of the chip faster than that.
R600 should be the biggest and the fastest-clocked chip around but we still don’t know how it will compare to Nvidia's G80 chip. We do know that R600 will have more graphic features and will be more capable, but that doesn't necessarily mean faster in the frame-rendering battle.
The R600 is a faster version of the Xbox 360 chip with more shaders. It features Shader Model 4.0 and is fully DirectX 10 compatible.