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Review: ATI's Radeon X800 XT Platinum Edition

by Ryszard Sommefeldt on 4 May 2004, 00:00

Tags: ATi Technologies (NYSE:AMD)

Quick Link: HEXUS.net/qaxw

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Texture Filtering Image Quality - 4X, 8X and 16X aniso

Texture filtering image quality is analysed to make sure it's up to par with what the hardware is supposed to be capable of.

4X anisotropic filtering

4X aniso
FilterTest - High Quality - 4X Aniso - Click for full size .png (~1MB)

4X aniso
Serious Sam - High Quality - 4X Aniso - Click for full size .png (~2.4MB)


90 and 45° angles are those filtered at full 4X with everything else receiving 2X.

8X anisotropic filtering

8X aniso
FilterTest - High Quality - 8X Aniso - Click for full size .png (~1MB)

8X aniso
Serious Sam - High Quality - 8X Aniso - Click for full size .png (~2.4MB)


The angle adaptive nature of ATI's filtering algorithm is most evident in the following 8X and 16X modes, with the flower-like shape giving the game away. Easy angles for the hardware to calculate are filtered most aggressively.

16X anisotropic filtering

No aniso
FilterTest - High Quality - 16X Aniso - Click for full size .png (~1MB)

No aniso
Serious Sam - High Quality - 16X Aniso - Click for full size .png (~2.4MB)


See above.

Summary

If R420's aniso algorithm has been changed from what's present on R360, I can't spot it. Its angle adaptive, which is somewhat suboptimal in terms of maximum possible image quality, but that maximum image quality is something that even R420-class hardware doesn't attempt at speed. Angle based aniso is needed for both good image quality and playable or usable framerates. It's a scheme adopted by NVIDIA for NV40, so all competing hardware in this class does the same thing.