RV770 is the heart of the Radeon HD 4800 series. It’s based on the R6xx architecture, but is supposed to add additional performance and features. The R6xx series of chips, both the R600 and RV670, were substantially different from previous generations as ATI had decided to move the antialiasing processing from the ROPs to the shaders. It was suggested that this was the cause for the cards’ lackluster performance in heavy antialiasing and anisotropic filtering environments, even though the latter is handled by a completely different section of the GPU, texture units, and that the AA is not the problem but the AF.
Thus, it’s not really fair to blame the shaders for the drop in performance. Somehow stories have started going around that AMD has ”fixed” the performance when using antialiasing, which assume is really about the anisotropic filtering. It has been suggested that AMD has reverted back to making the ROPs handling the AA, but that doesn’t really make much sense if AF is the problem and not AA, right? Instead, we simply suggest that the fix is the increased number of texture units, something which has been known for a very long time.
There might be more to it though, we will just have to wait and see. It’s not impossible that AMD has made more changes to how AA and AF are handled to improve performance.
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