ATI’s RV775 Looking to Thrash Nvidia
According to http://en.expreview.com/2008/12/12/amd-rv775-ready-to-give-nvidia-a-punch.html#more-1623 ATI will be looking to give Nvidia a little more thrashing with their RV775.
the stream processors of RV775 will be increased to 840, and TMU increased to 48. It can be concluded that RV775 will feature 168 Stream Processing Units, and every 14 of Stream Processing Units forms a SIMD, so there would be 12 SIMD in total. Every SIMD contains 70 stream processors, which sounds more logical.
But how can this be done? It?s very likely that they have utilized the spare units of RV770, and reform the Stream Processing Units in some special way. AMD RV770 is designed based on repair structures technology. If you have a unit with 10 shader processors, actually build 11. In this way, the spare unit can work should there be a defect. (You could visit Anandtech for more details) During the time when RV770 is sold well, AMD has enough time to improve the rate of good product. But we have no idea about the decrease of transistors.
Basically, the increase of Stream Processors and TMUs would bring positive influence. The improvement of core clock is supposed to be great as well. The core clock of RV775XT goes up sharply from 750MHz (HD4870) to 900MHz, and the memory clock of GDDR5 gets up to 1400MHz(*4). The core clock of RV775Pro has also been upgraded to 725MHz, and memory clock updates to 1400MHz. RV775Pro might be using GDDR4.
Apparently, RV775XT is designed to fight GeForce GTX285 and put NVIDIA into a difficult situation. The informer doesn?t mention 1GB version, but it won?t be a big problem to add another 512MB GDDR5. (it rumors that AMD has ordered all GDDR5 chips that a memory manucturer produces in Q1 and Q2 next year). Probably RV775XT will be branded as Radeon HD5870. Real products are expected to be available late January, just after the new version of GTX200 Series.
AMD will launch RV775Pro in March 2009, while RV870 based on 40nm won?t be out before October 2009. No news indicates AMD will design single-card and dual-core products again, but why not?