Anisotropic Filtering on the 9500/9700

[Bovinicus]

I would like to see how these cards perform with the lower-quality method of anisotropic filtering. I have been using this method on my Radeon 8500 (Granted, it is the only one I can use), and I cannot see how trilinear filtering could improve over it. It already displays even the most distant and angled textures with excellent clarity. This could greatly improve the standings for the Radeon 9500 Pro compared to NVIDIA's Ti4200/4400 cards if one likes to enable these settings. I know I will probably be using the lower-quality method unless I can really see some kind of noticeable difference between the two. I even remember seeing a quote from someone at ATi saying that trilinear filtering is actually a waste of time in combination with their adaptive method because it performs some sort of redundant operation. Someone who has this card, and has tried both of these settings (If you wanna give it a try, that would be cool too), let me know what differences in quality you notice between the two settings.

 

[Spicedaddy]

This article has good comparisons.

 

[BFG10K]

and I cannot see how trilinear filtering could improve over it.

Enabling trilinear filtering in conjunction with anisotropic filtering lets the GPU take trilinear texel samples instead of bilinear ones. This has the effect of taking the samples from a smoothly blended mipmap transition which eliminates the moving line (mipmap boundary) problems that bilinear anisotropic can give you.

Having said that I use fast (bilinear) anisotropic on my Radeon 9700 Pro because honestly the image quality has been improved greatly compared to older Radeons in this mode. I can't see the transitions at all except on rare occasions where they appear as soft join lines in certain lighting situations. But really they don't bother me at all and the speed is incredible.

I assume that all 9xxx Radeons will look just as good as the 9700 Pro and I think that there's no reason to use quality anisotropic filtering. Of course the option's there if you would prefer to use it.

 

[Bovinicus]

Hrm, well I have noticed those lines, but only on rare occasions. Even my Radeon 8500 is pretty consistent in it's anisotropic filtering. It seemed like this was a bit more of a problem before some driver updates. When I said I don't see how it can improve, I didn't mean theoretically. I meant, bilinear anisotropic filtering does a good job in and of itself, and it will be quite hard to make improvements over it. Therefore, any improvements that are made will be minimal and not worth the extra performance hit.

 

[Bovinicus]

Thanks for that link spicedaddy. I find it EXTREMELY hard to notice any difference between performance and quality modes of AF. In the article, it says that it is a little more noticeable when moving around in the game if one is looking for it. If anyone can help me find a link to a review that shows what the performance drop using quality AF compared to performance AF is like, then I would appreciate it. Again, I think if performance AF offers significantly higher performance than quality mode, it will make ATi's cards that much more appealing compared to NVIDIA's. This is especially true since (According to the screenshots in the HardOCP link) NVIDIA's metod of AF isn't as good at any level.

 

[GoodRevrnd]

Play 1942... w/o AF on there are HORRIBLE moving lines EVERYWHERE when you move (moreso when in a vehicle). This happens on both ATI and nVidia cards.

 

[BFG10K]

When I said I don't see how it can improve, I didn't mean theoretically.

I meant both in theory and in practice.

I meant, bilinear anisotropic filtering does a good job in and of itself,

I agree but I'd also like to point out that earlier Radeon versions didn't perform it as well as the 9700 Pro does.

Therefore, any improvements that are made will be minimal and not worth the extra performance hit.

In the case of the 9700 Pro I agree with you 100%. In the case of the other Radeons I probably agree as well but not as strongly.

w/o AF on there are HORRIBLE moving lines EVERYWHERE when you move (moreso when in a vehicle).

You don't need anisotropic filtering to remove those problems; in fact, anisotropic filtering isn't even the best way to remove them. Trilinear filtering is. Enable that and the mipmaps will be smoothly blended and the lines will vanish.

 

[Bovinicus]

AMDMB has a comparison of the performance hit of quality AF compared to performance AF. The Radeon 9700 retains 90% of it's performance under performance mode. Under quality mode, it drops to 72% of it's original performance without anisotropic filtering. Jump to the performance hit section to see the comparison. The Ti4600 drops to a mere 47% of it's original performance with only 8x enable. I estimate something more like 43% if a 16x mode were to be implemented. Now, if ATi could only implement FSAA fragment style like Matrox did, that would be something to behold. 16x fragment AA & 16x adaptive AF, the performance would be phenominal, as would the IQ. Oh well, that's just wishful thinking. =)