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
Portal 2
Portal 2 continues the long and proud tradition of Valve’s in-house Source engine. While Source continues to be a DX9 engine, Valve has continued to upgrade it over the years to improve its quality, and combined with their choice of style you’d have a hard time telling it’s over 7 years old at this point. Consequently Portal 2’s performance does get rather high on high-end cards, but we have ways of fixing that…
Given Portal 2’s wide range of performance it’s possible to at least somewhat bog it down on the GPU side without any special tricks thanks to its heavier use of shaders than in past Valve titles. Given a fast enough card I believe we could hit the 300fps internal Source framerate cap on our testbed, but thankfully at 2560 we’re nowhere close. In any case at 2560 the 7970 is well into the stratosphere, delivering 128.9fps, which is 18% better than the GTX 580. Meanwhile at 1920 as with so many other benchmarks that lead shrinks, this time down to 11%. Meanwhile the 7970 enjoys a smaller lead over the 6970, beating it by only around 30% at either resolution.
The great thing about the Source engine is that it’s well studied, and by utilizing DirectX9 it’s open to a few more image quality enhancements than DX10+ games. We’ve always wanted to have a standard benchmark with more anti-aliasing than just MSAA, and Portal is the perfect candidate. So for the second part of this test, we’ve turned on Super Sample Anti-Aliasing (SSAA) through NVIDIA and AMD’s driver control panels. With SSAA the entire scene gets anti-aliased, going beyond just removing the jaggies at polygon edges and removing all signs of shader aliasing too, making Portal 2 a very good looking game.
As expected, SSAA makes the performance of everything tank. At 2560 the 7970 is well below 60fps, and every other single-GPU card is slower yet. Once we get down to 1920 performance finally reaches a point where it’s playable, as the 7970 reaches 72.2fps.
Compared to its competition, it’s interesting to note that we appear to have hit an entirely different set of bottlenecks by using SSAA. The 7970 leads the GTX 580 by 9% at both resolutions while it leads the 6970 by 25% under the same conditions. We believe that at this point we’re seeing the limitations of ROP performance, which would explain why the 7970’s lead diminishes versus both the GTX 580 and 6970. The additional bandwidth the 7970’s design affords the ROPs can only go so far until it once again becomes a matter of pixel pushing power.
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RussianSensation - Thursday, December 22, 2011 - link
I think his comment still stands. In terms of a performance leap, at 925mhz speeds at least, this is the worst improvement from 1 major generation to the next since X1950XTX -->2900XT. Going from 5870 to 6970 is not a full generation, but a refresh. So for someone with an HD5870 who wants 2x the speed increase, this card isn't it yet.jalexoid - Thursday, December 22, 2011 - link
How's OpenCL on Linux/*BSD? Because I fail to see real high performance use in Windows environments for any GPGPU.For GPGPU the biggest target should be still Linux/*BSD because they are the dominating platforms there....
R3MF - Thursday, December 22, 2011 - link
"Among the features added to Graphics Core Next that were explicitly for gaming, the final feature was Partially Resident Textures, which many of you are probably more familiar with in concept as Carmack’s MegaTexture technology."Is this feature exclusive to gaming, or is it an extension of a visualised GPU memory feature?
i.e. if running Blender on the GPU via the cycles renderer will i be able to load scenes larger than local graphics memory?
Ryan Smith - Thursday, December 22, 2011 - link
It's exclusive to graphics. Virtualized GPU memory is a completely different mechanism (even if some of the cache concepts are the same).With that said I see no reason it couldn't benefit Blender, but the benefits would be situational. Blender would only benefit in situations where it can't hold the full scene, but can somehow hold the visibly parts of the scene by using tiles.
R3MF - Friday, December 23, 2011 - link
cheers RyanFinally - Thursday, December 22, 2011 - link
...the 2nd generation HD8870 feat. GCN, 3W idle consumption and hopefully less load consumption than my current HD6870. Just let a company like Sapphire add a silent cooler and I'm happy.poohbear - Thursday, December 22, 2011 - link
Btw why didnt Anandtech overclock this card? it overclocks like a beast according to all the other review sites!Esbornia - Thursday, December 22, 2011 - link
Cause they want you to think this card sucks come on guys everybody in the internet knows this site sucks for reviews that are not from Intel products.SlyNine - Thursday, December 22, 2011 - link
lol troll. This site has prefered who ever had the advantage in what ever area. They will do a follow up of its OCing and when they first show a card they show it at stock only.I do not OC my videocards, whats the point in adding 5% more gain in games that are running maxed anyways.
RussianSensation - Thursday, December 22, 2011 - link
Is this comment supposed to be taken seriously? Go troll somewhere else.