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
Final Words
The launch of the Radeon HD 7970 has presented us with a great deal of data and even more subjects to consider, so it’s difficult in the best of times to try to whittle this down to a single conclusion. Nevertheless, based on our testing I believe there are two distinct conclusions to be drawn: the case for gaming, and the case for computing.
Gaming
At the end of the day the 7970 is specifically targeted as a gaming workhorse. Regardless of any architecture changes, what’s important is how fast the card is, how much it costs, whether it works correctly, and what its physical attributes are like. With respect to all of these aspects AMD has made an acceptable card, but this is not a groundbreaking product like we’ve seen in the past.
The fact of the matter is that since 2008 we’ve become spoiled by AMD’s aggressive pricing. More than anything else the low prices of the Radeon HD 4870 and Radeon HD 5870 made those products superstars thanks to their performance for the price and their undercutting of NVIDIA’s competing cards. The Radeon HD 5870 was definitely fast, but at $379 it was a steal, which is part of the reason prices for it never stabilized at that low a level.
At the same time the 7970 is not the 5870. The 5870 relative to both NVIDIA and AMD’s previous generation video cards was faster on a percentage basis. It was more clearly a next-generation card, and DX11 only helped to seal the deal. Meanwhile if you look at straight averages the 7970 is only around 15-25% faster than the GTX 580 in our tests, with its advantage being highly game dependent. It always wins at 2560 and 1920, but there are some cases where it’s not much of a win. The 7970’s domination of the 6970 is more absolute, but then again the 6970 is a good $200 cheaper at this point in time.
Meanwhile the presence of previous generation dual-GPU cards will continue to muddle the picture a bit further. We remain as sheepish as ever on multi-GPU cards and believe a high performance single GPU card is still a better investment in most situations, but there’s no denying that the GTX 590 and Radeon HD 6990 are quite capable cards today if you can put up with the noise and the inherent issues with alternate frame rendering.
Ultimately the past few years have seen AMD make great technical progress, but on the business side of things it’s NVIDIA that has made all the money. GCN will help AMD here by improving their professional product line, but the other part of that equation is for AMD to stop selling their cards for so little when they don’t have to. And this is what we’re seeing with the Radeon HD 7970. AMD has chosen to price the 7970 like a current generation card – it’s priced relative to a 3GB GTX 580 – and that’s a fair metric. What it isn’t is groundbreaking in any sense.
So at the end of the day AMD has once again retaken the performance crown for single-GPU cards, bringing them back to a position they last held nearly 2 years ago with the 5870. To that AMD deserves kudos, and if you’re in the market for a $500+ video card the 7970 is clearly the card to get – it’s a bit more expensive than the GTX 580, but it’s reasonably faster and cooler all at once. However if you’ve been waiting for 28nm GPUs to bring about another rapid decrease in video card prices as we saw with the 5870, you’re going to be waiting a bit longer.
Compute
The Radeon HD 7970 may be a gaming product, but today was just as much a launch for AMD’s Graphics Core Next architecture as it was for their new single-GPU king. GCN is the biggest architecture overhaul for AMD since R600 in 2007, and it shows. AMD has laid out a clear plan to seriously break into the GPU computing market and GCN is the architecture that will take them there. This is their Fermi moment.
At this point I’m not comfortable speaking about the compute performance of GCN in absolutes, but based on our limited testing with the 7970 it’s clear the potential is there. At times it’s competitive with the Fermi-based GTX 580 and at other times it’s quite a bit faster. In the hands of experienced developers and given enough time to learn the quirks of GCN, I believe GCN will prove itself. It’s much too early to tell if it will be able to withstand the eventual arrival of NVIDIA’s Kepler, but certainly this is the best shot AMD has ever had.
Performance aside, it’s clear that AMD’s SIMD architecture will make GPU compute development for GCN much easier; of that there is no question. This is important as GCN isn’t just about HPC computing, it’s about fully embracing Fusion. AMD’s CPU plans are built upon GCN just as much as they’re built upon Bulldozer, and for GCN to deliver on its half of the heterogeneous computing aspect of Fusion it will need to be easy to program and it will need to perform well. It would appear AMD has the hardware to make the former happen, now time will tell if GCN Fusion can deliver on the latter.
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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...