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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haukionkannel - Thursday, December 22, 2011 - link
Well, 7970 and other GCN based new cards are not so much driver depended as those older radeons. So the improvements are not going to be so great, but surely there will be some! So the gap between 580 or 6970 vs 7970 is going to be wider, but do not expect as big steps as 6970 got via new sets of drivers.Ryan Smith - Thursday, December 22, 2011 - link
This is actually an excellent point. Drivers will still play a big part in performance, but with GCN the shader compiler in particular is now no longer the end all and be all of shader performance as the CUs can do their own scheduling.CeriseCogburn - Thursday, March 8, 2012 - link
I hate to say it but once you implement a 10% IQ cheat, it's though to do it again and get away with it again in stock drivers.I see the 797x has finally got something to control the excessive shimmering... that's about 5 years of fail finally contained...that I've more or less been told to ignore.... until the 100+ gig zip download here... to prove amd has at least finally dealt with one IQ epic fail... (of course all the reviewers claim there are no differences all the time - after pointing out the 10% cheat, then forgetting about it, having the shimmer, then "not noticing it in game" - etc).
I'm just GLAD amd finally did something about that particular one of their problems.
Halleluiah !
Now some PhysX (fine bullet or open cl but for pete sakes nvidia is also ahead on both of those!) and AA working even when cranking it to 4X plus would be great... hopefully their new arch CAN DO.
If I get a couple 7970's am I going to regret it is my question - how much still doesn't work and or is inferior to nvidia... I guess I'll learn to ignore it all.
IceDread - Thursday, December 22, 2011 - link
It's a good card, but for me it's not worth it to upgrade from a 5970 to a 7970. Looks like that would be about the same performance.Scali - Thursday, December 22, 2011 - link
This is exactly the reason why I made Endless City available for Radeons:http://scalibq.wordpress.com/2010/11/25/running-nv...
Could you run it and give some framerate numbers with FRAPS or such?
Boissez - Thursday, December 22, 2011 - link
What many seem to be missing is that it is actually CHEAPER than the current street prices on the 3GB-equiped GTX 580. IOW it offers superior performance, features, thermals, etc. at a lower price than current gen at a lower price.What AMD should do is get a 1.5 GB model out @450$ ASAP.
SlyNine - Thursday, December 22, 2011 - link
Looks like I'll be sticking with my 5870. I upgraded from 2 8800GT's ( that in SLI never functioned quite right because they were hitting over 100C ever with after market HSF) and enjoyed over 2x the performance.When I upgraded from a 1900XT to the 8800GT's same thing, 800XT-1900XT, 9700pro - 800XT, 4200(nvidia)-9700pro. The list goes on to my first Geforce 256 card.
Whats the point, My 5870 is 2! generations behind the 7970 yet this would be the worst $per increase in performance yet. Bummer I really want something to drive a new 120hz monitor, if I ever get one. But then thats kinda dependent on whether or not a single GPU can push it.
Finally - Thursday, December 22, 2011 - link
Since when do top-of-the-line cards give you the best FPS/$?For the last few months the HD6870+HD6850 were leading all those comparisons by quite some margin. The DH7970 will not change that.
SlyNine - Thursday, December 22, 2011 - link
If you read my post, you will notice that I'm compairing it to the improvments I have paid for in the past.40-60% Better than a 2 YO 5870 Is much worse than I have seen so far. Considering that its not just one generation but 2 generations beyond and for 500+$ to boot. This is the worst upgrade for the cost I have seen.....
SlyNine - Thursday, December 22, 2011 - link
The 6870 would not lead the cost per upgrade in performance at all, It would be in the negitives for me.