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
Crysis: Warhead
Kicking things off as always is Crysis: Warhead. It’s no longer the toughest game in our benchmark suite, but it’s still a technically complex game that has proven to be a very consistent benchmark. Thus even 4 years since the release of the original Crysis, “but can it run Crysis?” is still an important question, and the answer continues to be “no.” While we’re closer than ever, full Enthusiast settings at a 60fps is still beyond the grasp of a single-GPU card.
This year we’ve finally cranked our settings up to full Enthusiast quality for 2560 and 1920, so we can finally see where the bar lies. To that extent the 7970 is closer than any single-GPU card before as we’d imagine, but it’s going to take one more jump (~20%) to finally break 60fps at 1920.
Looking at the 7970 relative to other cards, there are a few specific points to look at; the GTX 580 is of course its closest competitor, but we can also see how it does compared to AMD’s previous leader, the 6970, and how far we’ve come compared to DX10 generation cards.
One thing that’s clear from the start is that the tendency for leads to scale with the resolution tested still stands. At 2560 the 7970 enjoys a 26% lead over the GTX 580, but at 1920 that’s only a 20% lead and it shrinks just a bit more to 19% at 1680. Even compared to the 6970 that trend holds, as a 32% lead is reduced to 28% and then 26%. If the 7970 needs high resolutions to really stretch its legs that will be good news for Eyefinity users, but given that most gamers are still on a single monitor it may leave AMD closer to 40nm products in performance than they’d like.
Speaking of 40nm products, both of our dual-GPU entries, the Radeon HD 6990 and GeForce GTX 590 are enjoying lofty leads over the 7970 even with the advantage of its smaller fabrication process. To catch up to those dual-GPU cards from the 6970 would require a 70%+ increase in performance, and even with a full node difference it’s clear that this is not going to happen. Not that it’s completely out of reach for the 7970 once you start looking at overclocking, but the reduction in power usage when moving from TSMC 40nm to 28nm isn’t nearly large enough to make that happen while maintaining the 6970’s power envelope. Dual-GPU owners will continue to enjoy a comfortable lead over even the 7970 for the time being, but with the 7970 being built on a 28nm process the power/temp tradeoff for those cards is even greater compared to 40nm products.
Meanwhile it’s interesting to note just how much progress we’ve made since the DX10 generation though; at 1920 the 7970 is 130% faster than the GTX 285 and 170% faster than the Radeon HD 4870. Existing users who skip a generation are a huge market for AMD and NVIDIA, and with this kind of performance they’re in a good position to finally convince those users to make the jump to DX11.
Finally it should be noted that Crysis is often a good benchmark for predicting overall performance trends, and as you will see it hasn’t let us down here. How well the 7970 performs relative to its competition will depend on the specific game, but 20-25% isn’t too far off from reality.
Looking at our minimum framerates it’s a bit surprising to see that while the 7970 has a clear lead when it comes to average framerates the minimums are only significantly better at 2560. At that resolution the lowest framerate for the 7970 is 23.5 versus 20 for the GTX 580, but at 1920 that becomes a 2fps, 5% difference. It’s not that the 7970 was any less smooth in playing Crysis, but in those few critical moments it looks to be dipping a bit more than the GTX 580.
Compared to the 6970 on the other hand the minimum framerate difference is much larger and much more consistent. At 2560 the 7970’s minimums are 29% better, and even at lower resolutions it holds at around 25%. Clearly even with AMD’s new architecture their designs still inherit some of the traits of their old designs.
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Zingam - Thursday, December 22, 2011 - link
And at the time when it is available in D3D. AMD's implementation won't be compatible... :D That's sounds familiar. So will have to wait for another generation to get the things right.Ryan Smith - Thursday, December 22, 2011 - link
As for your question about FP64, it's worth noting that of the FP64 rates AMD listed for GCN, "0" was not explicitly an option. It's quite possible that anything using GCN will have at a minimum 1/16th FP64.Sind - Thursday, December 22, 2011 - link
Excellent review thanks Ryan. Looking forward to see what the 7950 performance and pricing will end up. Also to see what nv has up their sleeves. Although I can't shake the feeling amd is holding back.chizow - Thursday, December 22, 2011 - link
Another great article, I really enjoyed all the state-of-the-industry commentary more than the actual benchmarks and performance numbers.One thing I may have missed was any coverage at all of GCN. Usually you guys have all those block diagrams and arrows explaining the changes in architecture. I know you or Anand did a write-up on GCN awhile ago, but I may have missed the link to it in this article. Or maybe put a quick recap in there with a link to the full write-up.
But with GCN, I guess we can close the book on AMD's past Vec5/VLIW4 archs as compute failures? For years ATI/AMD and their supporters have insisted it was the better compute architecture, and now we're on the 3rd major arch change since unified shaders, while Nvidia has remained remarkably consistent with their simple SP approach. I think the most striking aspect of this consistency is that you can run any CUDA or GPU accelerated apps on GPUs as old as G80, while you even noted you can't even run some of the most popular compute apps on 7970 because of arch-specific customizations.
I also really enjoyed the ISV and driver/support commentary. It sounds like AMD is finally serious about "getting in the game" or whatever they're branding it nowadays, but I have seen them ramp up their efforts with their logo program. I think one important thing for them to focus on is to get into more *quality* games rather than just focusing on getting their logo program into more games. Still, as long as both Nvidia and AMD are working to further the compatibility of their cards without pushing too many vendor-specific features, I think that's a win overall for gamers.
A few other minor things:
1) I believe Nvidia will soon be countering MLAA with a driver-enabled version of their FXAA. While FXAA is available to both AMD and Nvidia if implemented in-game, providing it driver-side will be a pretty big win for Nvidia given how much better performance and quality it offers over AMD's MLAA.
2) When referring to active DP adapter, shouldn't it be DL-DVI? In your blurb it said SL-DVI. Its interesting they went this route with the outputs, but providing the active adapter was definitely a smart move. Also, is there any reason GPU mfgs don't just add additional TMDS transmitters to overcome the 4x limitation? Or is it just a cost issue?
3) The HDMI discussion is a bit fuzzy. HDMI 1.4b specs were just finalized, but haven't been released. Any idea whether or not SI or Kepler will support 1.4b? Biggest concern here is for 120Hz 1080p 3D support.
Again, thoroughly enjoyed reading the article, great job as usual!
Ryan Smith - Thursday, December 22, 2011 - link
Thanks for the kind words.Quick answers:
2) No, it's an active SL-DVI adapter. DL-DVI adapters exist, but are much more expensive and more cumbersome to use because they require an additional power source (usually USB).
As for why you don't see video cards that support more than 2 TMDS-type displays, it's both an engineering and a cost issue. On the engineering side each TMDS source (and thus each supported TMDS display) requires its own clock generator, whereas DisplayPort only requires 1 common clock generator. On the cost side those clock generators cost money to implement, but using TMDS also requires paying royalties to Silicon Image. The royalty is on the order of cents, but AMD and NVIDIA would still rather not pay it.
3) SI will support 1080P 120Hz frame packed S3D.
ericore - Thursday, December 22, 2011 - link
Core Next: It appears AMD is playing catchup to Nvidia's Cuda, but to an extent that halves the potential performance metrics; I see no other reason why they could not have achieved at varying 25-50% improvement in FPS. That is going to cost them, not just for marginally better performance 5-25%, but they are price matching GTX 580 which means less sales though I suppose people who buy 500$ + GPUs buy them no matter what. Though in this case, they may wait to see what Nvidia has to offer.Other New AMD GPUs: Will be releasing in February and April are based on the current architecture, but with two critical differences; smaller node + low power based silicon VS the norm performance based silicon. We will see very similar performance metrics, but the table completely flips around: we will see them, cheaper, much more power efficient and therefore very quiet GPUs; I am excited though I would hate to buy this and see Nvidia deliver where AMD failed.
Thanks Anand, always a pleasure reading your articles.
Angrybird - Thursday, December 22, 2011 - link
any hint on 7950? this card should go head to head with gtx580 when it release. good job for AMD, great review for Ryan!ericore - Thursday, December 22, 2011 - link
I should add with over 4 billion transistors, they've added more than 35% more transistors but only squeeze 5-25% improvement; unacceptable. That is a complete fail in that context relative to advancement in gaming. Too much catchup with Nvidia.Finally - Thursday, December 22, 2011 - link
...that saying? It goes like this:If you don't show up for a race, you lose by default.
Your favourite company lost, so their fanboys may become green of envydia :)
Besides that - I'd never shell out more than 150€ for a petty GPU, so neither company's product would have appealed to me...
piroroadkill - Thursday, December 22, 2011 - link
Wait, catchup? In my eyes, they were already winning. 6950 with dual BIOS, unlock it to 6970.. unbelievable value.. profit??Already has a larger framebuffer than the GTX580, so...