AMD Radeon HD 7870 GHz Edition & Radeon HD 7850 Review: Rounding Out Southern Islands
by Ryan Smith on March 5, 2012 12:01 AM ESTCompute Performance
Moving on from our look at gaming performance, we have our customary look at compute performance. With GCN AMD significantly overhauled their architecture in order to improve compute performance, as their long-run initiatives rely on GPU compute performance becoming far more important than it is today.
Our first compute benchmark comes from Civilization V, which uses DirectCompute to decompress textures on the fly. Civ V includes a sub-benchmark that exclusively tests the speed of their texture decompression algorithm by repeatedly decompressing the textures required for one of the game’s leader scenes. Note that this is a DX11 DirectCompute benchmark.
The Civ V compute shader benchmark once again shows off just how much the compute shader performance of the 7800 series has improved relative to the 6900 series, with both 7800 cards coming in well, well ahead of any previous generation AMD cards. Compared to NVIDIA’s lineup the 7800 series does fairly well for itself too, although not quite as well as the commanding lead the 7900 series took.
Our next benchmark is SmallLuxGPU, the GPU ray tracing branch of the open source LuxRender renderer. We’re now using a development build from the version 2.0 branch, and we’ve moved on to a more complex scene that hopefully will provide a greater challenge to our GPUs.
SmallLuxGPU continues to showcase the 7800 series’ improvements over past AMD architectures, and while it’s not the same kind of massive leap we saw with CivV, it’s still enough to bring the 7850 up to near the performance of the 6970, and pushing the 7870 well beyond that. The only real competition here for AMD is AMD.
For our next benchmark we’re looking at AESEncryptDecrypt, an OpenCL AES encryption routine that AES encrypts/decrypts an 8K x 8K pixel square image file. The results of this benchmark are the average time to encrypt the image over a number of iterations of the AES cypher.
On the one hand, the 7870 gets quite close to the 7950 here in our AESEncryptDecrypt benchmark, in spite of the latter’s higher number of shaders. On the other hand, it’s still not enough to dethrone the GTX 570; the only NVIDIA cards the 7800 series can beat start at the GTX 560 Ti.
Finally, our last benchmark is once again looking at compute shader performance, this time through the Fluid simulation sample in the DirectX SDK. This program simulates the motion and interactions of a 16k particle fluid using a compute shader, with a choice of several different algorithms. In this case we’re using an (O)n^2 nearest neighbor method that is optimized by using shared memory to cache data.
In our final compute test the 7800 series once again makes a run at the top, with both cards rising past the GTX 570, although they can’t quite match the GTX 580. In an interesting turn of events the 7870 ends up being some 6% faster than the 7950, in spite of the fact that in a compute benchmark the 7950 should have a solid lead. This just goes to show that core clockspeeds do matter, and that adding more shaders alone can’t conquer all benchmarks.
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Taft12 - Monday, March 5, 2012 - link
Or don't. It's not on sale for 2 weeks yet.MySchizoBuddy - Monday, March 5, 2012 - link
NOT with 1/16 the FP64 performance.Zoomer - Wednesday, March 7, 2012 - link
FP64 is useless for games for the foreseeable future.CeriseCogburn - Thursday, March 8, 2012 - link
I love the "further image quality improvements page" which delicately and carefully explains how amd did a wonderful job of making things better as the image quality degrades...After noting the degredation very, very lightly and tossing out the problem, it is declared "unnoticable" for "all intents and purposes".
Eventually amd's IQ is going to be so far behind nvidia's the endless denials and it doesn't matters - will just continue since amd can crank an extra 20 fps doing it...
LOL
A "gift" from amd.
MySchizoBuddy - Monday, March 5, 2012 - link
where is the double precision compute benchmarksCeriseCogburn - Friday, March 9, 2012 - link
Article: " As AMD began winding down Cayman (6900 series) almost immediately with the launch of the 7900 series, at this point the 6900 market has effectively dried up. Having taken themselves out of competition with themselves, AMD’s only competition is NVIDIA’s lineup."--
And there we have it - AMD and their evil plot to squeeze every last dollar out of those "they care about", the gamers...
I don't want to hear Nvidia is evil anymore.
Time to look in the mirror amd users.
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Furthermore, it's time the reviewers start slamming AMD the way they slam Nvidia, in this case, one can consider it PRAISE for AMD "drying up their own card channels"- and if that isn't bias I don't know what is.
dagamer34 - Monday, March 5, 2012 - link
These cards don't seem like such a wonderful value considering what the 6900 series was offering, but since those cards have gone poof, I guess you'll have to settle for the 7800 series? It really just seems like they are adjusting their pricing scheme to be less compressed than it was before.TL: DR; If you've got a 6900 series card, the 7000 series is not for you.
Jedi2155 - Monday, March 5, 2012 - link
I still have my wonderful 5870 I purchased in 2009 (which now is not far from 3 years ago...), and still waiting for something that offers more performance than the 7970. Com'on Nvidia! Blow everything out of the water please....Death666Angel - Monday, March 5, 2012 - link
"TL: DR; If you've got a 6900 series card, the 7000 series is not for you."I'd say the 30 to 50% increase of the 79xx to 69xx cards could be well worth it. However, unless you run a multi-monitor setup or have a 2560 resolution, you really should think twice about spending that amount of money on these cards. But I guess people with that kind of cash can either do their own thinking or don't have to care too much about spending and can afford to "BUY ALL THE CARDS".
I'm still running a HD5770 and have a newly acquired 27" monitor here that is really stressing it. I think I'll go for a 78xx and later upgrade to CF because my 550W PSU can handle it with these cards, whereas HD69xx would be stressing it too much. :-)
cactusdog - Monday, March 5, 2012 - link
"TL: DR; If you've got a 6900 series card, the 7000 series is not for you."Thats the dumbest statement I have ever read here. The 7970 is DOUBLE the performance of the 6970 with overclocking. Even the $250 7850 beats the 6970 with overclocking.
The 7 series is the biggest performance jump over the previous series since I have followed graphics cards, since 1998.