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Old 07-07-04, 11:18 PM   #16
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Join Date: May 2003
Posts: 665
Default Re: NV40 Anistropic Filtering Investigation

Thanks for sharing ChrisRay!

Notice that, when trilinear and anisotropic filtering optimizations are BOTH enabled in either the High Performance or Performance modes, that the 6800 has a very small hit in performance when 8xAF or 16xAF is applied.

One thing that I have wondered about for some time now is why the ATI X800 cards seem to take such a small hit in performance vs the 6800 cards in certain Direct3D games when AF is applied. Particularly in games like UT2003, UT2004, FarCry, etc. I now suspect that these relatively small performance drops may be due to some degree to software/driver optimizations that ATI has implemented for the X800 cards in their newer Catalyst drivers. It seems that ATI is using both trilinear and anisotropic optimizations ENABLED by default (with no obvious way to turn these optimizations off), and this could be one reason why we see such relatively small hits to performance on these cards when AF is applied in certain D3D games. It almost seems as if the X800 cards in their default mode are doing less work than the 6800 cards in their default mode when AF is applied in-game. Also note that these relatively small performance hits on the X800 cards vs the 6800 cards when AF is applied does not hold true with OGL games.

Now the real question is, would it be equitable to compare the 6800 cards in Performance mode with anisotropic and trilinear optimizations enabled against the X800 cards, given the details mentioned in the paragraph above?

Most pro reviewers have decided to bench with the default driver settings from both ATI and NV. However, I have yet to see a detailed analysis done by a pro reviewer showing the effects in performance and/or image quality when cycling through the various modes that NV has to offer.

ChrisRay, when you have some time, it would be very interesting to see how fps changes in FarCry when you use the various modes detailed in your review. I suspect that we would see a relatively small performance hit when AF is applied to the 6800 cards if the aniso and tri optimizations are both enabled in the drivers.

Finally, generally, what are your thoughts on the image quality on the 6800 when using performance mode with tri and aniso optimizations enabled?
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