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.
Facebook
Twitter
RSS
173 Comments
View All Comments
ET - Monday, March 5, 2012 - link
I agree it's kind of disappointing. Even a 5750 was a good improvement over a 3870, and here there's nothing approaching this kind of performance benefit over the 5870 from these. Though I think part of it is that the 5870 still holds up well in many games, as these benchmarks show.Kjella - Monday, March 5, 2012 - link
I don't think it's that terrible... the 7870 fits pretty much the exact same power envelope as the 5850 and is starting to be a pretty solid performance upgrade. Yes it's a $350 card but inflation adjusted the $279 (pre-hike) 5850 is nearing $300 in 2012 dollars. A good deal and a good cooler (the reference cooler on the 5850 works, but is hardly quiet) and they may get a sale. Just waiting for Ivy Bridge, if nVidia hasn't shown a stunning Kepler by then I think the 7870 is it.Death666Angel - Tuesday, March 6, 2012 - link
Average increase of 40% in performance and you are comparing a high-end graphics card to a mid-range graphics card.DominionSeraph - Monday, March 5, 2012 - link
So, AMD discontinued the $250 6950 and $350 6970 to give us... a $250 6950 and $350 6970.Not exactly impressed.
Looks like it will be up to Nvidia to save us, just as they saved us from the price-gouged 5000 series with aggressive release price of the GTX 460 with price drops on the GTX 470. (That one action set the pricing scheme throughout the 6000/500 series)
CloudFire - Monday, March 5, 2012 - link
I'm not upgrading this cycle but I do wish to see Kepler out sooner to drive down prices. This is business and AMD has a few months of no competition so they are going to do all they can to reap massive profits.Nvidia isn't going to save you, they would do the same thing if they were in AMD's position. Remember nearly 5 years back with the 8800GTX going for 500+ for over a year? Yea......
DominionSeraph - Tuesday, March 6, 2012 - link
A halo product with no competition is beside the point. We're talking about the 7800 series which sits right in a range where there are competing products, and AMD is pricing it to suck you dry.The fact is that the 7000 series is not undercutting the 500 series the way Nvidia undercut the 5000 series. A $250 7850 vs a $270 + free Batman Arkham City GTX 560 Ti 448 Cores is about equal price/performance (maybe a tad in the favor of Nvidia). Contrast this to the GTX 460 being released at $200 when the 5770 was $180. The GTX 460 blew the doors off the 5770 and instantly said the appropriate price for that card is ~$130. A few months later we were seeing $110 5770's and $150 GTX 460's, and that's where we've been at ever since.
AMD refuses to aggressively compete with Nvidia. They simply slot their products into Nvidia's pricing structure. So prices only change when Nvidia drops theirs and AMD is forced to follow. This means that we, the consumers, are dependent on Nvidia to save us, because AMD sure as hell won't.
Exodite - Tuesday, March 6, 2012 - link
Not really a valid point of comparison though.Looking through several reviews of the 7800-series the 7850 lies closer to a 570 than a 560 Ti most of the time, while offering more and better in every possible category.
Sure, the 7850 isn't on the market yet but assuming the ~250 USD pricing holds true I couldn't possibly recommend a 560 Ti, or even 448 core version, over the 7850 with a straight face.
It could still be cheaper, sure, but it's nowhere near the pricing disaster the 7900 and 7700 series are.
To my mind the 7800 series were the ones to wait for.
Granted, with a 6950 myself I won't be upgrading until the 8k-series at the earliest. Unless Kepler turns out truly amazing, and brings triple display functionality on a single card.
tipoo - Monday, March 5, 2012 - link
If I recall Nvidia hasn't really under-priced AMD in recent memory, they've always tried x more performance sold for >x price.ET - Monday, March 5, 2012 - link
"AMD discontinued the $250 6950 and $350 6970 to give us... a $250 6950 and $350 6970."When you put it this way, it's quite a likeable upgrade actually. Slight boost in performance, lower power and better thermals, upgraded features, all for the same price. What's not to like?
chizow - Monday, March 5, 2012 - link
What's not to like is it took them 16 months to put out a greener refresh sidegrade.