GT200: Nvidia GeForce GTX 280 analysis

Anisotropic Filtering performance

Texture filtering quality hasn't moved on since the release of the GeForce 8800 GTX, as Nvidia managed to not only get rid of its filtering woes, but also managed to deliver the highest quality anisotropic filtering with a very respectable performance impact.

We're happy to report that the filtering quality on GeForce GTX 280 is identical to the GeForce 8800 Ultra in the side-by-side tests we've done, so if you're looking for comparisons, we'd recommend heading back to our original G80 architecture analysis where we cover filtering quality in detail.

Today's focus is on performance and we've run a number of tests to show how GT200's filtering hardware works when high anisotropic filtering levels are enabled. The first of those tests is D3D RightMark's built-in fillrate tester – we used this with varying AF levels to calculate the theoretical throughput.


We used eight textures to test anisotropic filtering performance in D3D RightMark and there were a few surprises in this test. We found that texture fillrate dropped off much sharper on the GTX 280, but even then it still ended up delivering slightly higher performance than the GeForce 9800 GTX once 16xAF was enabled. We first thought we were colour fillrate limited to some extent, but then we saw a similar pattern at 1,600 x 1,200 as well.


We chose Crysis for this particular test, as it was the first game for a long time where we've not been able to just 'set and forget' 16xAF. Based on the results obtained here, anisotropic filtering performance scales rather linearly on the GeForce GTX 280, while there's quite a sharp drop on the GeForce 9800 GX2. Interestingly though, both the 9800 GTX and 8800 Ultra maintained fairly steady frame rates across the board, dropping just five percent overall.