FUD Zilla reports ATI's Evergreen DX11 (RV870) GPU will be announced in late September, but that it will be soft launch without broad availability of the cards. The site claims the RV870 won't be available in significant quantity until Q4 2009. This could mean October, while NVIDIA's GT300 isn't expected until November.
This will occur in the last days of Q3 2009, while significant shipments and cards in volume should come in Q4 2009. Nvidia won’t have its “GT300” card before late Q4 2009, probably November time, but there is a strong feeling that Nvidia might end up faster.