The brand new ATI HD5870 using the RV870 which will be launch later in July this year supporting the upcoming release of DirectX 11 in Windows 7. As expected to be using back the 40nm GPU but with much more shader unit and higher clock, expected to delivery monster performance.

No wonder AMD already warned its manufacturers not to overclock the HD4770 or else it will be stepping on its own foot. AMD seems to want to maintain a balance performance/price ratio of all their cards. It seems like all its gone for Nvidia but however, their claim gtx 300 increase in performance over the GTX295 may send ATI back home crying(With massive price cuts that it).

HD 5870 Reference
GPU clock - 900 MHz
Memory clock - 1100 MHz
Performance - 2160 Gflops
Texture fillrate 43.200 MT/s
Pixel fillrate - 28.800 MP/s
Bandwidth - 140,8 GB/s

Source : http://www.hardware-infos.com/news.php?news=2908