[McG]

The latest leak suggests a massive upgrade from the HD 5700 series. Codenamed Barts XT, the HD 6770 features 320 VLIW-4 shader clusters, i.e. 1280 SP. It features the same ROP count (32) and memory bus (256-bit) as the HD 5870, though TMU count is dropped to 64 (from 80). The core clock is a whopping 900 MHz, making it the fastest stock speed of any discrete GPU. The memory clock and thus bandwidth is a shade lower than the HD 5870, at 134.4 GB/s. Barts Pro, branded HD 6750, features 280 clusters, or 1120 SP and 56 TMU and a much lower clock speed of 725 MHz, though the memory speed is only 50 MHz lower at 1 GHz. Incidentally, these clock speeds are identical to the HD 5850.

If these specifications are true, the end result is a HD 6770 card which soundly defeats a HD 5850, as recent rumours suggest, and gets very close to a HD 5870. Thanks to the more efficient shader clusters, all of this performance is achieved from a smaller die than Cypress using lower power - despite the same 40nm process. These are pretty staggering improvements for what was once rumoured to be a "minor refresh", which further questions the accuracy of these new rumours.

Izvor: VR-Zone i PCinlife