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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Galidou - Monday, March 5, 2012 - link
Yep, this must be the best price/performance ratio the 7xxx series has to offer yet but still nothing worth of buying unless you got a 3 years old plus video card...7870 priced at 300$ I wouldn't mind changing my 6850 crossfire for one of those considering the wattage and temperature of my actual setup. I was considering a gtx580 as they can be found on ebay for around 400$ used but this 7870 is around the same in every game I play at the resolution I play them. Plus the 2gb memory and cheaper price tag for a new one...
But I'll still wait for the price to drop or switch to kepler if price/performance is amazing... Heard it should be but it's all speculation on something that's not out yet...
chizow - Tuesday, March 6, 2012 - link
Only took 4th product launch from AMD for you to see what I was saying was true, but better late than never. ;)But yeah the real value right now is the last-gen parts going EOL and selling for extremely low prices. The 6950/6970s are mostly dried up in the channel, but there were GTX 480s for $219 last week, up next on the chopping block should be the 560Ti448/570/580 for great prices ahead of Kepler's launch.
Galidou - Tuesday, March 6, 2012 - link
I never said that you were totally wrong, I was only saying that it's not the worst thing that's ever happened in computer's history, while you were making a freaking case of it because I spoke against Nvidia...And you still can't name even an older radeon card in your short list of cheap video cards to get... At 130$ and 160$ for a radeon 6850 and 6870 respectively you still get ALOT for what you pay for. Radeon 6870 isn't far from gtx 560ti. Why mentioning it when you're being paid by the green goblin, they would stop sending your fanboy checks I guess, just teasing :P
There's one thing extraordinary about this gen, the size plus wattage used for THAT kind of performance... is quite amazing, it should just be priced accordingly to it's die size and it would be dirt cheap LOL... but no bang for your bucks here...while in this segment of the market where you usually ''get it all'' about price/performance ratio. Lower the price of 50$ for every 7xxx video card and it will be ALOT better.
BPB - Monday, March 5, 2012 - link
If nothing else I gotta believe that the new nVidia cards will force a quick price adjustment from AMD. I think we'll see the AMD cards drop $25 to $50 when the nvidia cards come out.CeriseCogburn - Friday, March 9, 2012 - link
After running blackbox 2.3 and wenning to the Turkish site I find something very interesting on Kepler:" Nvidia 's next-generation family of Kepler frequencies, dynamic graphics cards needed to improve their own work. Rumor has officially been confirmed as yet have the ability to dynamically overclock Kepler cards will leave a strong impact in the markets."
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LOL - Dynamic Overclocking of Kepler similar to Intel turbo... very nice Nvidia...
http://translate.google.com/translate?hl=en&sl...
mak360 - Monday, March 5, 2012 - link
"but $199 for a GTX 560 Ti is going to be hard to pass up while it lasts" I see you have to get a boot in there to AMD when possible. lolMost of the games are nvidia optimized where the 7850 loses one or two to the 560ti old tech.
AMD`s been quite merciful to nvidia in regards to price points, when nvidia brings it on and the same happens (cards slot in without a challenge to AMD) I call shady business between the two or they don`t want to compete with each other, which is understandable i guess..
Or maybe people need to forget the past and move on with "oh how nice and cheap prices were"
sofreshsoclean2 - Monday, March 5, 2012 - link
smoking card, faster than the 6970, fast as a gtx580 in a lot of those test but 150 smackeroos cheaper It is very close 7950 as well, finally a super fast card that is not 500 bucks. amazing card!! and nice review.thanks
Devoteicon - Monday, March 5, 2012 - link
Upgrade my overclocked 5850 for one of these? Thanks but no thanks.geniusloci - Monday, March 5, 2012 - link
I'm going to be getting one or the other. I'll have to decide if the 7870 is worth the additional cash or not. They will most assuredly drop in price once Nvidia launches its product. Having come from a 560Ti this will feel something like a side grade in performance, but having found out how much better ATIs cards do 2D and video I simply can't return to the blurry mess which is Nvidia right now.Kiste - Monday, March 5, 2012 - link
So it's 2012 and AMD gives us two cards that do little more than match the GTX 570 and 580 in price/performance.Southern Island has been a huge disappointment so far.