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
Display Tech: HD3D Eyefinity, MST Hubs, & DDM Audio
With the launch of the HD 5000 series back in 2009 AMD managed to get the drop on everyone, press and NVIDIA alike. Eyefinity, AMD’s Single Large Surface technology, came out of virtually nowhere thanks to a carefully orchestrated development plan that ensured very few people even within AMD knew about it. As a result of everything that was leaked ahead of time Eyefinity was not, making it AMD’s big eye catcher for the 5000 series.
As what was to be the first piece of the much dreamed about holodeck, AMD has been steadily working on it since 2009 in order to improve the experience even within their existing hardware by adding support for such features as bezel compensation and combining CrossFire with Eyefinity. For AMD it’s a feature of great importance even if end user adoption is still limited.
For the Southern Islands family AMD isn’t going to be pulling quite the rabbit out of their hat this time when it comes to displays. Southern Islands’ new display feature will be Discrete Digital Multi-Point Audio (which we’ll get to in a moment), but this doesn’t mean that AMD hasn’t continued to work on Eyefinity. Since October AMD has been engaged in an initiative they’re calling “Eyefinity Technology 2.0”, which is going to be pushed as a big part of the Southern Islands launch even though these are software improvements that will benefit all cards.
So what is Eyefinity Technology 2.0 composed of? We’ve already seen several new features starting with Catalyst 11.10, such as 5x1 portrait and landscape support and flexible bezel compensation support. The next step is going to be integrating Stereo 3D (or as AMD likes to call it, HD3D) into the mix, similar to how NVIDIA has 3D Vision Surround. Catalyst 11.12 introduced the ability to use HD3D with an Eyefinity display setup, and Catalyst 12.1 (preview out now) added support to do that in a CrossFire configuration. The final step is going to be with Catalyst 12.2 in February, which will add support for custom resolutions and the ability to relocate the Windows task bar to an arbitrary screen, two features that users have been asking about for quite some time. Again, all of these improvements are driver side, but they are a major component of AMD’s marketing for Southern Islands.
Speaking about Eyefinity, one issue that comes up time and time again is Multi Stream Transport (MST) hubs. We were introduced to MST hubs back with the launch of the 6800 series, which allowed a single DP 1.2 port to drive up to 4 monitors by taking advantage of the high bandwidth of DP1.2 and embedding transport streams for several monitors into the signal. The purpose of MST hubs was so that users could use several monitors with a regular Radeon card, rather than needing an exotic all-DisplayPort “Eyefinity edition” card as they need now.
But as many of you have asked me about, several deadlines for MST hubs have come and gone, including the latest deadline which was supposed to be by the end of this year. As with active DP adaptors this is largely out of AMD’s hands since they don’t produce the hardware, but they have been continuing to prod their partners on the issue. The latest deadline from AMD isn’t rosy – summer of 2012 – but they seem more confident of this deadline than deadlines in the past. Not that another half-year wait will be of any comfort for users who have been looking for MST hubs for the better part of the year, but at least it provides some idea on when to expect them.
Last, but certainly not least on the display technologies front is AMD’s new feature for Southern Islands, Discrete Digital Multi-Point Audio (DDMA). It’s a mouthful of a name but the concept is rather simple: it’s the next step in audio output from a video card. Video cards have been able to output audio for a few years now via HDMI, and more recently DisplayPort gained the ability. However GPUs have been limited to streaming audio to a single device, be it a monitor, TV, or receiver. With DDMA GPUs can send audio to multiple devices, and AMD is looking at how to put that ability to work.
The most basic use for being able to send audio to multiple devices is to individually address the speakers of each device, which is the cornerstone of AMD’s proposed use cases. Fundamentally AMD is looking at applications that involve matching audio streams to the monitor the relevant application is on – move a video player from your center monitor to your left monitor, and the audio from that video player should also move from the speakers on the middle monitor to the speakers on the left monitor. What can you do with speakers that are mapped to monitors? That’s what AMD wants to find out.
Being realistic for a moment, the 7970 isn’t going to be the card that sells this feature, as it’s a $550 gamer video card. Gamers are using dedicated 2.1/5.1/7.1 audio systems or headphones for surround sound, and while AMD does have a proposed multi-tasking use case for this it’s not very convincing. DDMA will become much more important on future lower end cards as those are the cards that go into family desktops, workstations, and the like. Thus the killer app for this feature (and certainly AMD’s best prepared scenario) is for video conferencing where each attendee is mapped to a monitor, and with DDMA a set of speakers on that monitor. AMD’s partner Oovoo is working on just such a system though it’s still early in development.
Facebook
Twitter
RSS
292 Comments
View All Comments
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...