AMD's Radeon HD 5870: Bringing About the Next Generation Of GPUs
by Ryan Smith on September 23, 2009 9:00 AM EST- Posted in
- GPUs
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.
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poohbear - Wednesday, September 23, 2009 - link
is it just me or is anyone else disappointed? next gen cards used to double the performance of previous gen cards, this card beats em by a measly 30-40%. *sigh* times change i guess.AznBoi36 - Wednesday, September 23, 2009 - link
It's just you.The next generations never doubled in performance. Rather they offered a bump in framerates (15-40%) along with better texture filtering, AA, AF etc...
I'd rather my games look AMAZING at 60fps rather than crappy graphics at 100fps.
SiliconDoc - Monday, September 28, 2009 - link
Golly, another red rooster lie, they just NEVER stop.Let's take it right from this site, so your whining about it being nv zone or fudzilla or whatever shows ati is a failure in the very terms claimed is not your next, dishonest move.
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NVIDIA w/ GT200 spanks their prior generation by 60.96% !
That's nearly 61% average increase at HIGHEST RESOLUTION and HIGHEST AA AF settings, and it right here @ AT - LOL -
- and they matched the clock settings JUST TO BE OVERTLY UNFAIR ! ROFLMAO AND NVIDIA'S NEXT GEN LEAP STILL BEAT THE CRAP OUT OF THIS LOUSY ati 5870 EPIC FAIL !
http://www.anandtech.com/video/showdoc.aspx?i=3334...">http://www.anandtech.com/video/showdoc.aspx?i=3334...
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roflmao - that 426.70/7 = 60.96 % INCREASE FROM THE LAST GEN AT THE SAME SPEEDS, MATCHED FOR MAKING CERTAIN IT WOULD BE AS LOW AS POSSIBLE ! ROFLMAO NICE TRY BUT NVIDIA KICKED BUTT !
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Sorry, the "usual" is not 15-30% - lol
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NVIDIA's last usual was !!!!!!!!!!!! 60.69% INCREASE AT HIGHEST SETTINGS !
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Now, once again, please, no lying.
piroroadkill - Wednesday, September 23, 2009 - link
No, it's definitely just youGriswold - Wednesday, September 23, 2009 - link
Its just you. Go buy a clue.ET - Wednesday, September 23, 2009 - link
Should probably be removed...Nice article. The 5870 doesn't really impress. It's the price of two 4890 cards, so for rendering power that's probably the way to go. I'll be looking forward to the 5850 reviews.
Zingam - Wednesday, September 23, 2009 - link
Good but as seen it doesn't play Crysis once again... :DWe shall wait for 8Gb RAM DDR 7, 16 nm Graphics card to play this damned game!
BoFox - Wednesday, September 23, 2009 - link
Great article!Re: Shader Aliasing nowhere to be found in DX9 games--
Shader aliasing is present all over the Unreal3 engine games (UT3, Bioshock, Batman, R6:Vegas, Mass Effect, etc..). I can imagine where SSAA would be extremely useful in those games.
Also, I cannot help but wonder if SSAA would work in games that use deferred shading instead of allowing MSAA to work (examples: Dead Space, STALKER, Wanted, Bionic Commando, etc..), if ATI would implement brute-force SSAA support in the drivers for those games in particular.
I am amazed at the perfectly circular AF method, but would have liked to see 32x AF in addition. With 32x AF, we'd probably be seeing more of a difference. If we're awed by seeing 16x AA or 24x CFAA, then why not 32x AF also (given that the increase from 8 to 16x AF only costs like 1% performance hit)?
Why did ATI make the card so long? It's even longer than a GTX 295 or a 4870X2. I am completely baffled at this. It only has 8 memory chips, uses a 256-bit bus, unlike a more complex 512-bit bus and 16 chips found on a much, much shorter HD2900XT. There seems to be so much space wasted on the end of the PCB. Perhaps some of the vendors will develop non-reference PCB's that are a couple inches shorter real soon. It could be that ATI rushed out the design (hence the extremely long PCB draft design), or that ATI deliberately did this to allow 3rd-party vendors to make far more attractive designs that will keep us interested in the 5870 right around the time of GT300 release.
Regarding the memory bandwidth bottleneck, I completely agree with you that it certainly seems to be a severe bottleneck (although not too severe that it only performs 33% better than a HD4890). A 5870 has exactly 2x the specifications of a 4890, yet it generally performs slower than a 4870X2, let alone dual-4890 in Xfire. A 4870 is slower than a 4890 to begin with, and is dependent on Crossfire.
Overall, ATI is correct in saying that a 5870 is generally 60% faster than a 4870 in current games, but theoretically, a 5870 should be exactly 100% faster than a 4890. Only if ATI could have used 512-bit memory bandwidth with GDDR5 chips (even if it requires the use of a 1024-bit ringbus) would the total memory bandwidth be doubled. The performance would have been at least as good as two 4890's in crossfire, and also at least as good as a GTX295.
I am guessing that ATI wants to roll out the 5870X2 as soon as possible and realized that doing it with a 512-bit bus would take up too much time/resources/cost, etc.. and that it's better to just beat NV to the punch a few months in advance. Perhaps ATI will do a 5970 card with 512-bit memory a few months after a 5870X2 is released, to give GT300 cards a run for its money? Perhaps it is to "pacify" Nvidia's strategy with its upcoming next-gen that carry great promises with a completely revamped architecture and 512 shaders, so that NV does not see the need to make its GT300 exceed the 5870 by far too much? Then ATI would be able to counter right afterwards without having to resort to making a much bigger chip?
Speculation.. speculation...
Lakku - Wednesday, September 23, 2009 - link
Read some of the other 5780 articles that cover SSAA image quality. It actually makes most modern games look worse, but that is through no fault of ATi, just the nature of the SS method that literally AA's everything, and in the process, can/does blur textures.strikeback03 - Wednesday, September 23, 2009 - link
I don't know much about video games, but in photography it is known that reducing the size of an image reduces the appearance of sharpness as well, so final sharpening should be done at the output size.