http://forums.vr-zone.com/news-around-the-web/418725-hd-4770-rv740-performance-price.html
AMD will launch the 40nm HD4770 in early May*, at under $99 excluding rebates. It will be based on the R700 core as are the rest of the HD4xxx series, but because it's a shrink from 55nm it will be much cheaper and cooler than its 55nm counterpart. Also coming is the slower HD4750* at a cheaper price, to replace the HD4830.
Graphics card scaling is roughly linear with shader count and clocks, so 640 shaders at 750MHz will be within 5% performance of the HD4850's 800 shaders at 625MHz. AMD's numbers show it averaging 20% faster (being conservative) than the card Nvidia positions against it, the 9800GT, while being slightly cheaper (cheapest non-rebate 9800GT I can find is $115).
It's funny (and the last slide refers to this), that the 9800GT is the same core as the 8800GTX which launched in 2006. This was die-shrunk to the 8800GT, renamed to the 9800GT for marketing reasons, and was going to be renamed AGAIN to the GTS240 but this was cancelled after the backlash Nvidia got from renaming the 9800GTX+ (itself an overclocked 9800GTX which was a die shrunk 8800GTX) to the GTS250. Nvidia's actual new architecture, GT200, is too hot and expensive to make into a competitor at this price point, and there's no word on new parts from Nvidia any time soon.
*Not mentioned on the slides.
