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
DirectX11 Redux
With the launch of the 5800 series, AMD is quite proud of the position they’re in. They have a DX11 card launching a month before DX11 is dropped on to consumers in the form of Win7, and the slower timing of NVIDIA means that AMD has had silicon ready far sooner. This puts AMD in the position of Cypress being the de facto hardware implementation of DX11, a situation that is helpful for the company in the long term as game development will need to begin on solely their hardware (and programmed against AMD’s advantages and quirks) until such a time that NVIDIA’s hardware is ready. This is not a position that AMD has enjoyed since 2002 with the Radeon 9700 and DirectX 9.0, as DirectX 10 was anchored by NVIDIA due in large part to AMD’s late hardware.
As we have already covered DirectX 11 in-depth with our first look at the standard nearly a year ago, this is going to be a recap of what DX11 is bringing to the table. If you’d like to get the entire inside story, please see our in-depth DirectX 11 article.
DirectX 11, as we have previously mentioned, is a pure superset of DirectX 10. Rather than being the massive overhaul of DirectX that DX10 was compared to DX9, DX11 builds off of DX10 without throwing away the old ways. The result of this is easy to see in the hardware of the 5870, where as features were added to the Direct3D pipeline, they were added to the RV770 pipeline in its transformation into Cypress.
New to the Direct3D pipeline for DirectX 11 is the tessellation system, which is divided up into 3 parts, and the Computer Shader. Starting at the very top of the tessellation stack, we have the Hull Shader. The Hull Shader is responsible for taking in patches and control points (tessellation directions), to prepare a piece of geometry to be tessellated.
Next up is the tesselator proper, which is a rather significant piece of fixed function hardware. The tesselator’s sole job is to take geometry and to break it up into more complex portions, in effect creating additional geometric detail from where there was none. As setting up geometry at the start of the graphics pipeline is comparatively expensive, this is a very cool hack to get more geometric detail out of an object without the need to fully deal with what amounts to “eye candy” polygons.
As the tesselator is not programmable, it simply tessellates whatever it is fed. This is what makes the Hull Shader so important, as it’s serves as the programmable input side of the tesselator.
Once the tesselator is done, it hands its work off to the Domain Shader, along with the Hull Shader handing off its original inputs to the Domain Shader too. The Domain Shader is responsible for any further manipulations of the tessellated data that need to be made such as applying displacement maps, before passing it along to other parts of the GPU.
The tesselator is very much AMD’s baby in DX11. They’ve been playing with tesselators as early as 2001, only for them to never gain traction on the PC. The tesselator has seen use in the Xbox 360 where the AMD-designed Xenos GPU has one (albeit much simpler than DX11’s), but when that same tesselator was brought over and put in the R600 and successive hardware, it was never used since it was not a part of the DirectX standard. Now that tessellation is finally part of that standard, we should expect to see it picked up and used by a large number of developers. For AMD, it’s vindication for all the work they’ve put into tessellation over the years.
The other big addition to the Direct3D pipeline is the Compute Shader, which allows for programs to access the hardware of a GPU and treat it like a regular data processor rather than a graphical rendering processor. The Compute Shader is open for use by games and non-games alike, although when it’s used outside of the Direct3D pipeline it’s usually referred to as DirectCompute rather than the Compute Shader.
For its use in games, the big thing AMD is pushing right now is Order Independent Transparency, which uses the Compute Shader to sort transparent textures in a single pass so that they are rendered in the correct order. This isn’t something that was previously impossible using other methods (e.g. pixel shaders), but using the Compute Shader is much faster.
Other features finding their way into Direct3D include some significant changes for textures, in the name of improving image quality. Texture sizes are being bumped up to 16K x 16K (that’s a 256MP texture) which for all practical purposes means that textures can be of an unlimited size given that you’ll run out of video memory before being able to utilize such a large texture.
The other change to textures is the addition of two new texture compression schemes, BC6H and BC7. These new texture compression schemes are another one of AMD’s pet projects, as they are the ones to develop them and push for their inclusion in DX11. BC6H is the first texture compression method dedicated for use in compressing HDR textures, which previously compressed very poorly using even less-lossy schemes like BC3/DXT5. It can compress textures at a lossy 6:1 ratio. Meanwhile BC7 is for use with regular textures, and is billed as a replacement for BC3/DXT5. It has the same 3:1 compression ratio for RGB textures.
We’re actually rather excited about these new texture compression schemes, as better ways to compress textures directly leads to better texture quality. Compressing HDR textures allows for larger/better textures due to the space saved, and using BC7 in place of BC3 is an outright quality improvement in the same amount of space, given an appropriate texture. Better compression and tessellation stand to be the biggest benefactors towards improving the base image quality of games by leading to better textures and better geometry.
We had been hoping to supply some examples of these new texture compression methods in action with real textures, but we have not been able to secure the necessary samples in time. In the meantime we have Microsoft’s examples from GameFest 2008, which drive the point home well enough in spite of being synthetic.
Moving beyond the Direct3D pipeline, the next big feature coming in DirectX 11 is better support for multithreading. By allowing multiple threads to simultaneously create resources, manage states, and issue draw commands, it will no longer be necessary to have a single thread do all of this heavy lifting. As this is an optimization focused on better utilizing the CPU, it stands that graphics performance in GPU-limited situations stands to gain little. Rather this is going to help the CPU in CPU-limited situations better utilize the graphics hardware. Technically this feature does not require DX11 hardware support (it’s a high-level construct available for use with DX10/10.1 cards too) but it’s still a significant technology being introduced with DX11.
Last but not least, DX11 is bringing with it High Level Shader Language 5.0, which in turn is bringing several new instructions that are primarily focused on speeding up common tasks, and some new features that make it more C-like. Classes and interfaces will make an appearance here, which will make shader code development easier by allowing for easier segmentation of code. This will go hand-in-hand with dynamic shader linkage, which helps to clean up code by only linking in shader code suitable for the target device, taking the management of that task out of the hands of the coder.
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mapesdhs - Saturday, September 26, 2009 - link
> That is quite all right, you fellas make sure to read it all, ...
But that's the thing S.D., I pretty much don't read any of it. :D (does
anyone?) First sentence only, then move on.
Ian.
SiliconDoc - Monday, September 28, 2009 - link
Oh, ha ha, another lowlife smart aleck.One has to wonder if you do as you say, and only read the first sentence, and move on, why you would care what I've typed, since you cannot imagine anyone does anything different. Heck you shouldn't even notice this, right liar ?
Yes, another liar, not amazing, not at all.
No need to modify or delete the sentence prior to this JaredWalton, smarty pants insulter won't read it, but I'm sure you can't resist, for "convenience's" sake of course.
Oh, I don't have to bring anything up on topic at all, because neither did lowlife skum not reading, he just got his nose awfully browner.
JarredWalton - Friday, September 25, 2009 - link
Very happy to have everyone here convinced you don't know what you're talking about? That's the only "truth" you've brought to this party. Marketing generally wants reputable people to promote a product - the "every man" approach. Funny that we don't see crazy people espousing products on TV (well, excepting stuff like Sham Wow!)Being crazy like you are in this thread only cements your status as someone who doesn't have a firm grip on reality - someone that can't be trusted. Thanks again for clearing that up so thoroughly.
I am very happy about it as well! :-D
erple2 - Tuesday, September 29, 2009 - link
Yeah, but that "Sham Wow" product works like a freakin' charm...http://www.popularmechanics.com/blogs/home_journal...">http://www.popularmechanics.com/blogs/home_journal...
SiliconDoc - Wednesday, September 30, 2009 - link
Im' sure you spend your time drooling in front of a TV after you spank your joystick for fps, so know all about wacky commercials you have memorized, and besides, it's a pathetic, all you have left insult, off topic, who cares, pure hatred, no real response, and the 5870 double epic fail IS THE HOTTEST ATI CARD OF ALL TIME!erple2 - Wednesday, September 30, 2009 - link
What's with the personal attacks? Does that mean that you concede defeat?Meh, you've no more credibility. Chill out.
SiliconDoc - Friday, September 25, 2009 - link
Yeah, now down to insults, since you lost everything else.Let's have your claimed specialty outlined here in context, let's have you come clean on LAPTOP GRAPHICS, and spread the truth about how NVIDIA is so far ahead and has been for quite some time, that it's a JOKE to buy a gaming laptop with ATI graphics on board.
Come on mmister!
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Now that is REALLY FUNNY ! You grabbed your arrogant unscrupulous self and proclaimed your fairness, but picked a spot where ati is completely EPIC FAIL, and NVIDIA is 1000% the only way to go, PERIOD, and left that MAJOR slap in the face high and dry.
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Great job, yeah, you're the "sane one".
LOL
dieselcat18 - Saturday, October 3, 2009 - link
Nvidia fan-boy, troll, loser....take your gforce cards and go home...we can now all see how terrible ATi is thanks you ...so I really don't understand why people are beating down their doors for the 5800 series, just like people did for the 4800 and 3800 cards. I guess Nvidia fan-boy trolls like you have only one thing left to do and that's complain and cry like the itty-bitty babies that some of you are about the competition that's beating you like a drum.....so you just wait for your 300 series cards to be released (can't wait to see how many of those are available) so you can pay the overpriced premiums that Nvidia will be charging AGAIN !...hahaha...just like all that re-badging BS they pulled with the 9800 and 200 cards...what a joke !.. Oh my, I must say you have me in a mood and the ironic thing is I do like Nvidia as much as ATi, I currently own and use both. I just can't stand fools like you who spout nothing but mindless crap while waving your team flag (my card is better than your's..WhaaWhaaWhaa)...just take yourself along with your worthless opinions and slide back under that slimly rock you came from.JarredWalton - Friday, September 25, 2009 - link
You've been insulting in this whole thread, so don't go crying to mamma about someone pointing that out. I did go and delete the posts from the person calling you gay and suggesting you should die in various ways, because as bad as you've been you haven't stooped quite that low (yet).Laptop issues with ATI... you mean http://www.anandtech.com/mobile/showdoc.aspx?i=356...">like this. Granted, I gave them a chance to address the issues. They failed and my full article on the various Clevo high-end notebooks will make it quite clear how far ahead NVIDIA is in the mobile sector right now.
"Fair" is treating both sides objectively. ATI has major problems with getting updated graphics drivers out on mobile products, and that's horrible. On the desktop, they don't have such issues for the most part. Yeah, you might have to wait a month or so for a driver update to fix the latest hot release and add CrossFire support... but you have to do the exact same thing for NVIDIA with about the same frequency. Only SLI and CF setups really need the regular driver updates, and in many cases the latest 18x and 19x NVIDIA drivers are slower than 16x and 17x on games that are older than six months.
Fair is also looking at these results and saying, "gee, I can get a 5870 for $400 (or $360 if you wait a few weeks for supply to bolster up), and that same card has no CrossFire or SLI wonkiness and costs less than the GTX 295 and 4870X2. Okay, 4870X2 and GTX 295 beat it in raw performance in some cases, but I don't think there's a single game where you can say one HD 5870 offers less than acceptable performance at 2560x1600, and I can guarantee there are titles that still have issues with SLI and CrossFire. (Yeah, you need to turn down some details in Crysis to get acceptable performance, but that's true of anything other than the top SLI and CF configs.) I would be more than happy to give up a bit of performance to avoid dealing with the whole multi-GPU ordeal. Why don't you tell us how innovative and awesome tri-SLI and quad-SLI are while you're at it?
At present, you have contributed more than 20% of the comments to this article, and not a single one has been anything but trolling. Screaming and yelling, insulting others, lying and making stuff up, all in support of a company that is just like any other big company. We don't ban accounts often, but you've more than warranted such action.
SiliconDoc - Friday, September 25, 2009 - link
I think it is more than absolutely clear, that in fact, I said my peace, my first post, and was absolutely attacked. I didn't attack, I got attacked, and in fact you have done plenty of attacking as well.I have also provided links, to back up my assertions and counter arguments, added the text for easy viewing, and pointed out in very specific detail whay issues with bias I had and why.
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Now you've claimed "all I've done is post FUD".
It is nothing short of amazing for you to even posit that, however I can certainly understand anyone pointing out the obvious bias problems (in the article no less) is "on thin ice", and after getting attacked, is solely blamed for "no facts".
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I certainly won't disagree that the 5870 is a good value as appearing if especially if you don't like to deal with 2 cards or 2 cores.
But my posts never claimed otherwise. I first claimed it was not as good as wanted, was disappointing, and therefore was not the end of what ati had in store.
Since I have posted on the 5890, which will in fact be 512 bit.
Now, you don't like losing your points, or someone adept enough, smart enough, and accurate enough to counter them.
Sorry about that, and sorry that I won't just lay down, as more heaps are shovelled my way.
You skip my actual points, and go some other tangent.
1. PhysX is an advantage and best implementation so far.
your response: "It sucks because only 2 games ar available"
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Is that correct for you to do ? Is it not the very best so far ? Yes, it is in fact.
I have remained factual and reasonable, and glad enough to throw back when I'm attacked.
But the fact remains, I have made absolutely solid 100% poijnts no matter how many times you claim " lying and making stuff up, "
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Yet of course, what I just said about NVIDIA and laptp chips, you agreed with. So accoring to your own characterization (quite unfair), all you do is scream and lie, too.
Just wonderful.
The GT300 is going to blow this 5870 away - the stats themselves show it, and betting otherwise is a bad joke, and if sense is still about, you know it as well.