AMD Radeon HD 7970 Review: 28nm And Graphics Core Next, Together As One
by Ryan Smith on December 22, 2011 12:00 AM EST- Posted in
- GPUs
- AMD
- Radeon
- ATI
- Radeon HD 7000
Civilization V
Our final game, Civilization 5, gives us an interesting look at things that other RTSes cannot match, with a much weaker focus on shading in the game world, and a much greater focus on creating the geometry needed to bring such a world to life. In doing so it uses a slew of DirectX 11 technologies, including tessellation for said geometry, driver command lists for reducing CPU overhead, and compute shaders for on-the-fly texture decompression.
Because of the fact that Civilization V uses driver command lists, we were originally not going to include it in this benchmark suite as a gaming benchmark. If it were solely a DCL test it would do a good job highlighting the fact that AMD doesn’t currently support the feature, but a poor job of actually explaining any hardware/architectural differences. It was only after we saw AMD’s reviewer’s guide that we decided to go ahead and include it, because quite frankly we didn’t believe the numbers AMD had published.
With the GTX 580 and the 6970, the 6970 routinely lost to the GTX 580 by large margins. We had long assumed this was solely due to NVIDIA’s inclusion of DCLs, as we’ve seen a moderate single-GPU performance deficit and equally moderate multi-GPU lead for AMD melt away when NVIDIA added DCL support. The 7970 required that we rethink this.
If Civilization V was solely a DCL test, then our 2560 results would be impossible – the 7970 is winning by 12% in a game NVIDIA previous won by a massive margin. NVIDIA only regains their lead at 1680, which at this resolution we’re not nearly as likely to be GPU-bound.
So what changed? AMD has yet to spill the beans, but short of a secret DCL implementation for just CivV we have to look elsewhere. Next to DCL CivV’s other killer feature is its use of compute shaders, and GCN is a compute architecture. To that extent we believe at this point that while AMD is still facing some kind of DCL bottleneck, they have completely opened the floodgates on whatever compute shader bottleneck was standing in their way before. This is particularly evident when comparing the 7970 to the 6970, where the 7970 enjoys a consistent 62% performance advantage. It’s simply an incredible turnabout to see the 7970 do so well when the 6970 did so poorly.
Of course if this performance boost really was all about compute shaders, it raises a particularly exciting question: just how much higher could AMD go if they had DCLs? Hopefully one day that’s an answer we get to find out.
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Scali - Saturday, December 24, 2011 - link
I have never heard Jen-Hsun call the mock-up a working board.They DID however have working boards on which they demonstrated the tech-demos.
Stop trying to make something out of nothing.
Scali - Saturday, December 24, 2011 - link
Actually, since Crysis 2 does not 'tessellate the crap' out of things (unless your definition of that is: "Doesn't run on underperforming tessellation hardware"), the 7970 is actually the fastest card in Crysis 2.Did you even bother to read some other reviews? Many of them tested Crysis 2, you know. Tomshardware for example.
If you try to make smart fanboy remarks, at least make sure they're smart first.
Scali - Saturday, December 24, 2011 - link
But I know... being a fanboy must be really hard these days..One moment you have to spread nonsense about how Crysis 2's tessellation is totally over-the-top...
The next moment, AMD comes out with a card that has enough of a boost in performance that it comes out on top in Crysis 2 again... So you have to get all up to date with the latest nonsense again.
Now you know what the AMD PR department feels like... they went from "Tessellation good" to "Tessellation bad" as well, and have to move back again now...
That is, they would, if they weren't all fired by the new management.
formulav8 - Tuesday, February 21, 2012 - link
Your worse than anything he said. Grow upCeriseCogburn - Sunday, March 11, 2012 - link
He's exactly correct. I quite understand for amd fanboys that's forbidden, one must tow the stupid crybaby line and never deviate to the truth.crazzyeddie - Sunday, December 25, 2011 - link
Page 4:" Traditionally the ROPs, L2 cache, and memory controllers have all been tightly integrated as ROP operations are extremely bandwidth intensive, making this a very design for AMD to use. "
Scali - Monday, December 26, 2011 - link
Ofcourse it isn't. More polygons is better. Pixar subdivides everything on screen to sub-pixel level.That's where games are headed as well, that's progress.
Only fanboys like you cry about it.... even after AMD starts winning the benchmarks (which would prove that Crysis is not doing THAT much tessellation, both nVidia and new AMD hardware can deal with it adequately).
Wierdo - Monday, January 2, 2012 - link
http://techreport.com/articles.x/21404"Crytek's decision to deploy gratuitous amounts of tessellation in places where it doesn't make sense is frustrating, because they're essentially wasting GPU power—and they're doing so in a high-profile game that we'd hoped would be a killer showcase for the benefits of DirectX 11
...
But the strange inefficiencies create problems. Why are largely flat surfaces, such as that Jersey barrier, subdivided into so many thousands of polygons, with no apparent visual benefit? Why does tessellated water roil constantly beneath the dry streets of the city, invisible to all?
...
One potential answer is developer laziness or lack of time
...
so they can understand why Crysis 2 may not be the most reliable indicator of comparative GPU performance"
I'll take the word of professional reviewers.
CeriseCogburn - Sunday, March 11, 2012 - link
Give them a month or two to adjust their amd epic fail whining blame shift.When it occurs to them that amd is actually delivering some dx11 performance for the 1st time, they'll shift to something else they whine about and blame on nvidia.
The big green MAN is always keeping them down.
Scali - Monday, December 26, 2011 - link
Wrong, they showed plenty of demos at the introduction. Else the introduction would just be Jen-Hsun holding up the mock card, and nothing else... which was clearly not the case.They demo'ed Endless City, among other things. Which could not have run on anything other than real Fermi chips.
And yea, I'm really going to go to SemiAccurate to get reliable information!