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
Civilization V
Our final game, Civilization 5, gives us an interesting look at things that other RTSes cannot match, with a much weaker focus on shading in the game world, and a much greater focus on creating the geometry needed to bring such a world to life. In doing so it uses a slew of DirectX 11 technologies, including tessellation for said geometry, driver command lists for reducing CPU overhead, and compute shaders for on-the-fly texture decompression.
Because of the fact that Civilization V uses driver command lists, we were originally not going to include it in this benchmark suite as a gaming benchmark. If it were solely a DCL test it would do a good job highlighting the fact that AMD doesn’t currently support the feature, but a poor job of actually explaining any hardware/architectural differences. It was only after we saw AMD’s reviewer’s guide that we decided to go ahead and include it, because quite frankly we didn’t believe the numbers AMD had published.
With the GTX 580 and the 6970, the 6970 routinely lost to the GTX 580 by large margins. We had long assumed this was solely due to NVIDIA’s inclusion of DCLs, as we’ve seen a moderate single-GPU performance deficit and equally moderate multi-GPU lead for AMD melt away when NVIDIA added DCL support. The 7970 required that we rethink this.
If Civilization V was solely a DCL test, then our 2560 results would be impossible – the 7970 is winning by 12% in a game NVIDIA previous won by a massive margin. NVIDIA only regains their lead at 1680, which at this resolution we’re not nearly as likely to be GPU-bound.
So what changed? AMD has yet to spill the beans, but short of a secret DCL implementation for just CivV we have to look elsewhere. Next to DCL CivV’s other killer feature is its use of compute shaders, and GCN is a compute architecture. To that extent we believe at this point that while AMD is still facing some kind of DCL bottleneck, they have completely opened the floodgates on whatever compute shader bottleneck was standing in their way before. This is particularly evident when comparing the 7970 to the 6970, where the 7970 enjoys a consistent 62% performance advantage. It’s simply an incredible turnabout to see the 7970 do so well when the 6970 did so poorly.
Of course if this performance boost really was all about compute shaders, it raises a particularly exciting question: just how much higher could AMD go if they had DCLs? Hopefully one day that’s an answer we get to find out.
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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.