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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.

Civilization V

Civilization V

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.

Starcraft II Compute: The Real Reason for GCN
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  • GenSozo - Thursday, December 22, 2011 - link

    Style? Another possibility is that he has no life, a heavily worn F5 key, and lots of angst. Reply
  • Blaster1618 - Monday, December 26, 2011 - link

    One request when diving into acronyms (from the “quick refresher”), first one is followed by (definition in parenthesis) or hyperlink. Your site does the best on the web at delving into and explaining the technical evolution of computing. You maybe even able to tech the trolls and shills a thing or to they can regurgitate at there post X-mas break circle jerk. Never underestimate the importance or reach of your work. Reply
  • Concillian - Thursday, December 22, 2011 - link

    Page 1
    Power Consumption Comparison: Columns: AMD / Price / NVIDIA

    Presumably mislabeled.
    Reply
  • Anand Lal Shimpi - Thursday, December 22, 2011 - link

    Fixed, thank you!

    Take care,
    Anand
    Reply
  • Penti - Thursday, December 22, 2011 - link

    Will the new video decode engine either add software accelerated gpu or fixed function hardware WebM/VP8 video decode? ARM SoC's basically already has those capabilities with rock-chip including hw-decoding, TI OMAP IVA3 DSP-video processor supporting VP8/WebM, Broadcom supporting it in their video processor and others to come. Would be odd to be able to do smooth troublefree 1080p WebM on a phone or tablet, but not a desktop and laptop computer without taxing the cpu and buses like crazy. It's already there hardware-wise in popular devices to do if they add software/driver support for it.

    Nice to see a new generation card any how.
    Reply
  • Ryan Smith - Thursday, December 22, 2011 - link

    It's UVD3, the same decoder that was on Cayman. So if Cayman can't do it, Tahiti can't either. Reply
  • MadMan007 - Thursday, December 22, 2011 - link

    Pretty sure the chart on the first page should be labeled Price Comparison not Power Consumption Comparison.

    Unless perhaps this was a sly way of saying money is power :)
    Reply
  • descendency - Thursday, December 22, 2011 - link

    You list the HD 6870 as 240 on the first page ("AMD GPU Specification Comparison" chart) but then list it as around 160 in the "Winter 2011 GPU Pricing Comparison" chart. 80 dollars is quite a difference. Reply
  • Anand Lal Shimpi - Thursday, December 22, 2011 - link

    Fixed, sorry those were older numbers.

    Take care,
    Anand
    Reply
  • gevorg - Thursday, December 22, 2011 - link

    37.9dB is a horrible testbed for noise testing! WTF! Reply

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