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.
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CeriseCogburn - Thursday, March 8, 2012 - link
Interesting, amd finally copied nvidia..." This problem forms the basis of this benchmark, and the NQueen test proves once more that AMD's Radeon HD 7970 tremendously benefits from leaving behind the VLIW architecture in complex workloads. Both the HD 7970 and the GTX 580 are nearly twice as fast as the older Radeons. "
When we show diversity we should also show that amd radeon has been massively crippled for a long time except when "simpleton" was the key to speed. "Superior architecture" actually means "simple and stupid" - hence "fast" at repeating simpleton nothings, but unable to handle "complex tasks".
LOL - the dumb gpu by amd has finally "evolved".
chizow - Thursday, December 22, 2011 - link
....unfortunately its going to be pitted against Kepler for the long haul.There's a lot to like about Southern Islands but I think its going to end up a very similar situation as Evergreen vs. Fermi, where Evergreen released sooner and took the early lead, but Fermi ultimately won the generation. I expect similar with Tahiti holding the lead for the next 3-6 months until Kepler arrives, but Kepler and its refresh parts winning this 28nm generation once they hit the streets.
Overall the performance and changes AMD made with Tahiti look great compared to Northern Islands, but compared to Fermi parts, its just far less impressive. If you already owned an AMD NI or Evergreen part, there'd be a lot of reason to upgrade, but if you own a Fermi generation Nvidia card there's just far less reason to, especially at the asking price.
I do like how AMD opened up the graphics pipeline with Tahiti though, 384-bit bus, 3GB framebuffer, although I wonder if holding steady with ROPs hurts them compared to Kepler. It would've also been interesting to see how the 3GB GTX 580 compared at 2560 since the 1.5GB model tended to struggle even against 2GB NI parts at that resolution.
ravisurdhar - Thursday, December 22, 2011 - link
My thoughts exactly. Can't wait to see what Kepler can do.Also...4+B transistors? mind=blown. I remember when we were ogling over 1B. Moore's law is crazy.... :D
johnpombrio - Wednesday, December 28, 2011 - link
Exactly. If you look at all the changes that AMD did on the card, I would have expected better results: the power consumption decrease with the Radeon 7970 is mainly due to the die shrink to 28nm. NVidia is planning on a die shrink of their existing Fermi architecture before Kepler is released:http://news.softpedia.com/news/Nvidia-Kepler-Is-On...
Another effect of the die shrink is that clock speed usually increases as there is less heat created at the lower voltage needed with a smaller transistor.
The third change that is not revolutionary is the bump of AMD's 7970's memory bus from 384 bits (matching the 580) from the 6970's 256 bits along with 3GB DDR5 memory vs the GTX580's 1.5GB and the 6970's 2GB.
The final non revolutionary change is bumping the number of stream processors by 33% from 1,536 to 2,048.
Again, breaking out my calculator, the 35% bump in the number of stream processors ALONE causes the increase in the change in the benchmark differences between the 7970 and the 6970.
The higher benchmark, however, does not show ANY OTHER large speed bumps that SHOULD HAVE OCCURED due to the increase in the memory bus size, the higher amount of memory, compute performance, texture fill rate, or finally the NEW ARCHITECTURE.
If I add up all the increases in the technology, I would have expected benchmarks in excess of 50-60% over the previous generation. Perhaps I am naive in how much to expect but, hell, a doubling of transistor count should have produced a lot more than a 35% increase. Add the new architecture, smaller die size, and more memory and I am underwhelmed.
CeriseCogburn - Thursday, March 8, 2012 - link
Well, we can wait for their 50%+ driver increase package+ hotfixes - because after reading that it appears they are missing the boat in drivers by a wide margin.Hopefully a few months after Kepler blows them away, and the amd fans finally allow themselves to complain to the proper authorities and not blame it on Nvida, they will finally come through with a "fix" like they did when the amd (lead site review mastas) fans FINALLY complained about crossfire scaling....
KaarlisK - Thursday, December 22, 2011 - link
What is the power consumption with multiple monitors? Previously, you could not downclock GDDR5, so the resulting consumption was horrible.Ryan Smith - Thursday, December 22, 2011 - link
"On that note, for anyone who is curious about idle clockspeeds and power consumption with multiple monitors, it has not changed relative to the 6970. When using a TMDS-type monitor along with any other monitor, AMD has to raise their idle clockspeeds from 350MHz core and 600Mhz memory to 350MHz core and the full 5.5GHz speed for memory, with the power penalty for that being around 30W. Matched timing monitors used exclusively over DisplayPort will continue to be the only way to be able to use multiple monitors without incurring an idle penalty."KaarlisK - Thursday, December 22, 2011 - link
Thank you for actually replying :)I am so sorry for having missed this.
ltcommanderdata - Thursday, December 22, 2011 - link
Great review.Here's hoping that AMD will implement 64-bit FP support across the whole GCN family and not just the top-end model. Seeing AMD's mobile GPUs don't use the highest-end chip, settling for the 2nd highest and lower, there hasn't been 64-bit FP support in AMD mobile GPUs since the Mobility HD4800 series. I'm interested in this because I can then dabble in some 64-bit GPGPU programming on the go. It also has implications for Apple since their iMacs stick to mobile GPUs, so would otherwise be stuck without 64-bit FP support which presumably could be useful for some of their professional apps.
In regards to hardware accelerated Megatexture, is it directly applicable to id Tech 5's OpenGL 3.2 solution? ie. Will id Tech 5 games see an immediate speed-up with no recoding needed? Or does Partially Resident Texture support require a custom AMD specific OpenGL extension? If it's the later, I can't see it going anywhere unless nVidia agrees to make it a multivendor EXT extension.
Ryan Smith - Thursday, December 22, 2011 - link
Games will need to be specifically coded for PRT; it won't benefit any current games. And you are correct in that it will require and AMD OpenGL extension to use (it won't be accessible from D3D at this time).