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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  • ilnot1 - Wednesday, September 23, 2009 - link

    In fact, going by the lowest Newegg prices, this is how the top setups would stack up today:

    5870 CF .......= $760
    GTX 285 SLI .= $592
    GTX 295 .......= $470
    GTX 275 SLI .= $420
    5870 ............= $380
    4890 CF ........= $360
    4870 X2 ........= $330

    This would make the 4890 CF or the 275 SLI setups the best value. And yes I realize there will be availability issues and price adjustments over the next month or so.
  • DominionSeraph - Thursday, September 24, 2009 - link

    you forgot:

    4870 CF: $260-280

    and how about the $180 4850 CF, which is probably the best price/performance for sub-1920x1200 gaming. http://www.anandtech.com/video/showdoc.aspx?i=3517...">http://www.anandtech.com/video/showdoc.aspx?i=3517... You can even get 1GB versions for ~$190.
  • ilnot1 - Wednesday, September 23, 2009 - link

    Another very good review, thanks.

    But piggy backing on what wicko said, I'm surprised you didn't include two 4890 in CF. Seeing as how you can get two 4890 for less than a 5870 (whenever they are actually available). $180 x 2 = $360 < $379. And this from Newegg, not some super special sale price.

    http://www.newegg.com/Product/Product.aspx?Item=N8...">http://www.newegg.com/Product/Product.aspx?Item=N8...
  • Ryan Smith - Wednesday, September 23, 2009 - link

    It's something we would have included if we had the cards. I don't have 2 4890s, and we couldn't get a second one in time.
  • AnotherGuy - Wednesday, September 23, 2009 - link

    as always anandtech rox
  • nbjsl2000 - Wednesday, September 23, 2009 - link

    Finally time to upgrade..
  • SiliconDoc - Wednesday, September 23, 2009 - link

    Not only all that, but when there were 13 big titles for PhysX and a hundred smaller ones, we were told here, "Meh", who needs it.
    Now, we have a papery and unavailable (egg)except by pre-order(tiger) 5870 launch, a not-existing 5850, with guess what ? NO DX11 games!
    Oh wait, there is actually just ONE - see page 7 of review. LOL
    ---
    Conclusion ?: " It looks like NO(err.. just one) DX11 games ready, so... it also looks like NVidia is launching at the right time, and ATI blew their dry unimpressive wad on a piece of paper porn. "
    ---
    Gee no one crowing about the first DX11 card... imagine that...

    Good thing , too, considering how 13 big or a hundred titles small of PhysX enhanced games was "nothing to change one's purchase decision over". At least Anand got addicted to Mirror's Edge with PhysX enabled before concluding in the article "meh" this PhysX thing is ok if you like this game, but who cares...
    ---
    Now we have the DX11 pre DX11 games launch with a paper product, so crowing about it wouldn't be too fitting, huh.

  • monomer - Wednesday, September 23, 2009 - link

    Why would a developer would release a DX11 game before DX11 is even available?
  • SiliconDoc - Friday, September 25, 2009 - link

    Why would a developer release a DX11 card before DX11 is even available ?
    (I suppose you'll have to unscrew your hate nvidia foil cap, and grind in the red spikes in it's place to answer that one.)
    However, allow me, instead.
    1.I have been running windows 7 32&64 for quite some time now, not sure why you haven't been.
    2. Battleforge, an ATI promo game, as noted in the review, has released their DX11 patch, hence, with W7 from MSFT (the beta+ free trial good till March 1st 2010 or something like that) I believe any gamer has had a reasonable chance to preview DX11.
    ---
    So anyway...
  • cactusdog - Friday, September 25, 2009 - link

    Ya , ATI has done it again. Excellent performance for a fair price. If Nvidia released this exact card it would be $150-$200 more expensive.
    LOL, Nvidia sales are gonna be slow for a while.

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