Angle-Independent Anisotropic Filtering At Last

For a number of years now the quality of anisotropic filtering has been slowly improving. Early implementations from AMD and NVIDIA were highly angle-dependent, resulting in a limited improvement to image quality from such filtering. The angle-dependent nature lead to shimmering and other artifacting that was not ideal.

As of the previous generation of cards, the quality of anisotropic filtering had become pretty good. NVIDIA’s best filtering mode was pretty close to angle-independent, and AMD’s only slightly worse. Neither was perfect, but neither was bad either.


The Radeon HD 4890


The GeForce GTX 285

However so long as no one had an angle-independent implementation, there was room to improve. And AMD has gone there. The anisotropic filtering algorithm used by the 5000 series is now truly and completely angle-independent. There are no more filtering tricks being used.


The Radeon HD 5870: Perfection

As you can see, the MIP maps in our venerable D3D AF Tester are perfectly circular, the hallmark of an angle-independent implementation. With angle-independent filtering, this effectively marks the end of the filtering arms race. AMD has won, and should NVIDIA catch up in the future the two would merely be tied. There’s nowhere left to go for quality beyond angle-independent filtering at the moment.

AMD tells us that there is no performance hit with their new algorithm compared to their old one. This is a bit hard to test since we can’t enable the old algorithm on the 5870, but certainly whatever performance hit there is, is similarly minor. In all of the testing we’re doing today, you will see results done with 16x anisotropic filtering used.

What you won’t see however is a difference, particularly with our static screenshots. When discussing the matter, AMD noted that the difference in perceived quality between the old algorithm and the new one was practically the same. After looking at matters we find ourselves in agreement with AMD; we were not able to come up with any situations where there was a noticeable difference, beyond the obvious AF quality tests that are designed to identify such changes.

Regardless of the outcome, AMD deserves kudos for making angle-independent anisotropic filtering happen. It’s demonstrably perfect filtering with no speed hit versus the previous generation of filtering; making it in essence a “free” improvement in image quality, however slight the real-world results are. We’re always ready to get better image quality out of our video cards, after all.

More GDDR5 Technologies: Memory Error Detection & Temperature Compensation The Return of Supersample AA
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  • dieselcat18 - Saturday, October 3, 2009 - link

    It truly amazes me that AnandTech allows a Troll like you to keep posting...but there is always one moron that comes to a forum like this and shows his a** to the world...So we all know it to be you...nice work not bringing anything resembling an intelligent discussion to the table..Oh and please don't tell me what it is that I bring to the conversation...my thoughts about this topic have nothing to do with my reply to you about your vulgar manner and lack of respect for anyone that has a difference of opinion.
    Oh and as for you paper launch...well sites like Newegg were sold out immediately because of the overwhelming demand for this card and I'll bet you anything there are cards available and in good supply at this very moment...Why don't you take a look and give us all another update.....I guess having that big "L" stamped on your forehead sums it up.....
  • SiliconDoc - Wednesday, September 23, 2009 - link

    No, they didn't, because the 5870's just showed up last night, 4 of them, and just a bit ago the ONE of them actually became "available", the Powercolor brand.
    The other three 5870's are NOT AVAILABLE but are listed....
    So "ATI paper launch" is the key idea here (for non red roosters).
    1:43 PM CST, Wed. Sept. 23rd, 2009.
    ---
    Yes, I watched them appear on the egg last night(I'm such a red fanboy I even love paper launches)... LOL
  • crimson117 - Wednesday, September 23, 2009 - link

    Current cheapest GTX 295 at Newegg is $469.99.

    http://www.newegg.com/Product/Product.aspx?Item=N8...">http://www.newegg.com/Product/Product.a...p;cm_re=...
  • B3an - Wednesday, September 23, 2009 - link

    Ryan, on your AA page, you have an example of the unofficial Nvidia SSAA where the tree branches have gone missing in HL2. And say because of this it's not suitable for general use.

    But for both the ATI pics, on either MSAA or SSAA, the tree branches are missing as well. Did you not notice this? because you do not comment on it.

    Either way it looks like ATI AA is still worse, or there is a bug.
  • Ryan Smith - Wednesday, September 23, 2009 - link

    We used the same save game, but not the same computer. These were separate issues we were chasing down at the same time, so they're not meant to be comparable. In this case I believe some of the shots were at 1600x1200, and others were at 1680x1050. The result of which is that the widescreen shots are effectively back a bit farther due to the use of the same FOV at all times in HL2.

    As you'll see in our Crysis shots, there's no difference. I can look in to this issue later however, if you'd like.
  • chizow - Wednesday, September 23, 2009 - link

    Really enjoyed the discussion of the architecture, new features, DX11, Compute Shaders, the new AF algorithm and the reintroduction of SSAA an ATI parts.

    As for the card itself, its definitely impressive for a single-GPU but the muted enthusiasm in your conclusion seems justified. Its not the definite leader for single-card performance as the 295 is still consistently faster and the 5870 even fails to consistently outperform its own predecessor, the 4870X2.

    Its scaling problems are really odd given its internals and overall specs seem to indicate its just RV790 CF on a single die, yet it scales worst than the previous generation in CF. I'd say you're probably onto something thinking AMD underestimated the 5870's bandwidth requirements.

    Anyways, nice card and nice effort from AMD, even if its stay at the top is short-lived. AMD did a better job pricing this time around and will undoubtedly enjoy high sales volume with little competition in the coming months with Win 7's launch, up until Nvidia is able to counter with GT300.
  • chizow - Wednesday, September 23, 2009 - link

    Holy....lol

    I didn't even realize til I read another comment that Ryan Smith wrote this and not Anand/Derek collaboration. That's a compliment btw, it read very Anand-esque the entire time! ;-) Really enjoyed it similar to some of your earlier efforts like the 3-part Vista memory investigation.
  • formulav8 - Wednesday, September 23, 2009 - link

    I wouldn't be surprised if most of us already knew what was going to take place with performance and what-not. But its still a nice card whether I knew the specs before its official release or not. (And viewed many purposely leak benches). :)


    Jason
  • PJABBER - Wednesday, September 23, 2009 - link

    Another fine review and nice to see it hit today. Your reviews are one reason I keep coming back to AT!

    Unfortunately, at MSRP the 5870 doesn't offer enough for me to move past the 4890 I am currently using, and bought for $130 during one of the sales streaks a month or so ago. Will re-evaluate when we actually start seeing price drops and/or DX11 games hit the shelves.

  • wicko - Wednesday, September 23, 2009 - link

    It would have been nice to see 4890 in CF against 5870 in CF. 500$ spent vs 800$ spent :p

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