|A reader sent me a rather long e-mail the other day and after a very avid discussion about what could be the specifications for the upcoming RV770, we came to the conclusion that there is a great mismatch between the rumors circulating here in the west and what the people closer to industry sources are saying. The 480 shader processors and 32TMUs we've been so certain of may not be as accurate as we thought. There have been many elaborations as to what the new core would be like, and after the very interesting discussion, I have to admit some of the most recent news post may have been misleading.
EDIT: Not an April fool's joke
If you're worried about the number of TMUs, you can calm down. This is the one thing where we all pretty much agree, 32. We've reported on more than one occasion that the number of unified shaders would be bumped to 480 shader processors, whereas our Eastern friends are elaborating that they will instead increase by 480. This means that the RV770 would actually feature 800 unified shaders. This may sound like a bizarre increase, but I will try to walk you through their reasoning.
First of all, their expecting an evolution much like the one we had when we moved from the R520 (X1800) to R580 (X1900). At the same time, they expect the texture unit:ALU ratio to increase from 1:4 to 1:5. Even if the shader ratio would remain 1:4, we would still be left with twice as many unified shaders, 640. R520 has a 1:1 ratio, R580 1:3, R600/RV670 1:4, while RV770 will go one step beyond with 1:5. Speculation of course, be they seem quite convinced that this is the way it is.
The extra shaders may also be able to improve the quite poor antialiasing performance as well. If implemented efficiently, they should be able to remedy at least parts of the lackluster performance during heavy AA. It is believed that an overall better optimized core should be able to boost AA performance substantially.
The number of transistors is expected to land in the 830 million area, a 25 percent increase of the 666 million transistors RV670 sport.
We will just have to wait until late May when the card should surface.