While AMD and NVIDIA are consistently revising their GPU architectures, for the most part the changes they make are just that: revisions. It’s only once in a great while that a GPU architecture is thrown out entirely, which makes the arrival of a new architecture a monumental occasion in the GPU industry. The last time we saw this happen was in 2006/2007, when unified shaders and DirectX 10 lead to AMD and NVIDIA developing brand new architectures for their GPUs. Since then there have been some important revisions such as AMD’s VLIW4 architecture and NVIDIA’s Fermi architecture, but so far nothing has quite compared to 2006/2007, until now.

At AMD’s Fusion Developer Summit 2011 AMD announced Graphics Core Next, their next-generation GPU architecture. GCN would be AMD’s Fermi moment, where AMD got serious about GPU computing and finally built an architecture that would serve as both a graphics workhorse and a computing workhorse. With the ever increasing costs of high-end GPU development it’s not enough to merely develop graphics GPUs, GPU developers must expand into GPU computing in order to capture the market share they need to live well into the future.

At the same time, by canceling their 32nm process TSMC has directed a lot of hype about future GPU development onto the 28nm process, where the next generation of GPUs would be developed. In an industry accustomed to rapid change and even more rapid improvement never before have GPU developers and their buyers had to wait a full 2 years for a new fabrication process to come online.

All of this has lead to a perfect storm of anticipation for what has become the Radeon HD 7970: not only is it the first video card based on a 28nm GPU, but it’s the first member of the Southern Islands and by extension the first video card to implement GCN. As a result the Radeon HD 7970 has a tough job to fill, as a gaming card it not only needs to deliver the next-generation performance gamers expect, but as the first GCN part it needs to prove that AMD’s GCN architecture is going to make them a competitor in the GPU computing space. Can the 7970 do all of these things and live up to the anticipation? Let’s find out…

AMD GPU Specification Comparison
  AMD Radeon HD 7970 AMD Radeon HD 6970 AMD Radeon HD 6870 AMD Radeon HD 5870
Stream Processors 2048 1536 1120 1600
Texture Units 128 96 56 80
ROPs 32 32 32 32
Core Clock 925MHz 880MHz 900MHz 850MHz
Memory Clock 1.375GHz (5.5GHz effective) GDDR5 1.375GHz (5.5GHz effective) GDDR5 1.05GHz (4.2GHz effective) GDDR5 1.2GHz (4.8GHz effective) GDDR5
Memory Bus Width 384-bit 256-bit 256-bit 256-bit
Frame Buffer 3GB 2GB 1GB 1GB
FP64 1/4 1/4 N/A 1/5
Transistor Count 4.31B 2.64B 1.7B 2.15B
Manufacturing Process TSMC 28nm TSMC 40nm TSMC 40nm TSMC 40nm
Price Point $549 $350 $160 -

The Radeon HD 7970 is a card of many firsts. It’s the first video card using a 28nm GPU. It’s the first card supporting Direct3D 11.1. It’s the first member of AMD’s new Southern Islands Family. And it’s the first video card implementing AMD’s Graphics Core Next architecture. All of these attributes combine to make the 7970 quite a different video card from any AMD video card before it.

Cutting right to the chase, the 7970 will serve as AMD’s flagship video card for the Southern Islands family. Based on a complete AMD Tahiti GPU, it has 2048 stream processors organized according to AMD’s new SIMD-based GCN architecture. With so many stream processors coupled with a 384bit GDDR5 memory bus, it’s no surprise that Tahiti is has the highest transistor count of any GPU yet: 4.31B transistors. Fabricated on TSMC’s new 28nm High-K process, this gives it a die size of 365mm2, making it only slightly smaller than AMD’s 40nm Cayman GPU at 389mm2.

Looking at specifications specific to the 7970, AMD will be clocking it at 925MHz, giving it 3.79TFLOPs of theoretical computing performance compared to 2.7TFLOPs under the much different VLIW4 architecture of the 6970. Meanwhile the wider 384bit GDDR5 memory bus for 7970 will be clocked at 1.375GHz (5.5GHz data rate), giving it 264GB/sec of memory bandwidth, a significant jump over the 176GB/sec of the 6970.

These functional units are joined by a number of other elements, including 8 ROP partitions that can process 32 ROPs per clock, 128 texture units divided up among 32 Compute Units (CUs), and a fixed function pipeline that contains a pair of AMD’s 9th generation geometry engines. Of course all of this hardware would normally take quite a bit of power to run, but thankfully power usage is kept in check by the advancements offered by TSMC’s 28nm process. AMD hasn’t provided us with an official typical board power, but we estimate it’s around 220W, with an absolute 250W PowerTune limit. Meanwhile idle power usage is looking particularly good, as thanks to AMD's further work on power savings their typical power consumption under idle is only 15W. And with AMD's new ZeroCore Power technology (more on that in a bit), idle power usage drops to an asbolutely miniscule 3W.

Overall for those of you looking for a quick summary of performance, the 7970 is quite powerful, but it may not be as powerful as you were expecting. Depending on the game being tested it’s anywhere between 5% and 35% faster than NVIDIA’s GeForce GTX 580, averaging 15% to 25% depending on the specific resolution in use. Furthermore thanks to TSMC’s 28nm process power usage is upwards of 50W lower than the GTX 580, but it’s still higher than the 6970 it replaces. As far as performance jumps go from new fabrication processes, this isn’t as big a leap as we’ve seen in the past.

In a significant departure from the launch of the Radeon HD 5870 and 4870, AMD will not be pricing the 7970 nearly as aggressively as those cards with its launch. The MSRP for the 7970 will be $550, a premium price befitting a premium card, but a price based almost exclusively on the competition (e.g. the GTX 580) rather than one that takes advantage of cheaper manufacturing costs to aggressively undercuts the competition. In time AMD needs to bring down the price of the card, but for the time being they will be charging a price premium reflecting the card’s status as the single-GPU king.

For those of you trying to decide whether to get a 7970, you will have some time to decide. This is a soft launch; AMD will not make the 7970 available until January 9th (the day before the Consumer Electronics Show), nearly 3 weeks from now. We don’t have any idea what the launch quantities will be like, but from what we hear TSMC’s 28nm process has finally reached reasonable yields, so AMD should be in a better position than the 5870 launch. The price premium on the card will also help taper demand side some, though even at $550 this won’t rule out the first batch of cards selling out.

Beyond January 9th, AMD as an entire family of Southern Islands video cards still to launch. AMD will reveal more about those in due time, but as with the Evergreen and Northern Islands families AMD has a plan to introduce a number of video cards over the next year. So 7970 is just the beginning.

Winter 2011 GPU Pricing Comparison
  $750 GeForce GTX 590
Radeon HD 6990 $700  
Radeon HD 7970 $549  
  $500 GeForce GTX 580
Radeon HD 6970 $350 GeForce GTX 570
Radeon HD 6950 2GB $250  
  $240 GeForce GTX 560 Ti
Radeon HD 6870 $160  


A Quick Refresher: Graphics Core Next


View All Comments

  • Scali - Monday, December 26, 2011 - link

    Lol, how's that, when I'm the one saying that AMD's cards are the best performers in Crysis 2?
    I'm neutral, a concept that is obviously alien to you. Idiots...
  • Scali - Monday, December 26, 2011 - link

    Heck, I'm also the guy who made Endless City run on non-nVidia cards. How does that make me an nVidia fanboy? Reply
  • CeriseCogburn - Thursday, March 08, 2012 - link

    That's sad when an nvidia fanboy has to help all the amd fannies with software coding so they can run a benchmark, then after all that work to help the underprivileged, nothing but attacks after the facts... finally silence them.
    It's really sad when the truth is so far from the pop culture mind that actually speaking it is nearly forbidden.
    Thank you for helping them with the benchmark. Continue to be kind in such ways to the sour whining and disgruntled, as it only helped prove how pathetic amd dx11 was...
  • james007 - Friday, December 30, 2011 - link

    This sounded like such an awesome card and I was psyched to get it the moment it comes out -- until reading the part about dropping the 2nd DVI port. A DisplayPort-to-SLDVI doesn't do it, for me, because my desktop has to drive two 30" displays. In fact, I would love to be able to drive a third display so I can have a touch-screen also. My current (previous-generation) VDC does drive both displays just fine.

    This does not seem like such an infrequent requirement, especially for high-end users. Why would they drop the ability to drive the 2nd display? !!!

  • The_Countess666 - Saturday, December 31, 2011 - link

    not trying to sell you anything but, HDMI to dual-link dvi does exist (see link, or google yourself for other shops).

    and these cards do have 1 HDMI-out so that should work for you.
  • Penti - Wednesday, January 04, 2012 - link

    It's the IHV that makes those decisions any way, just because it's not on a reference card doesn't mean they won't show up or that you can't build a card with it. But the HDMI supports more then 1920x1200 finally on this card any how. I guess they could deliver a card with the old type of DVI>HDMI adapters. Obviously opting for HDMI and multidisplaycapable displayport 1.2 makes more sense though. It's been around for years now. Reply
  • Penti - Wednesday, January 04, 2012 - link

    Just make sure you actually has the number of connections you need when buying the card, many 7970 bords only appear to support single-link DVI on the DVI-connector. Reply
  • poordirtfarmer2 - Wednesday, January 04, 2012 - link

    Enjoyed the article.

    So this new 79XX architecture is about a GPU architecture that’s also good for “compute work”. The reference to NVIDIA ‘s professional video cards (Quadro ; Telsa), implies to me that this might mean video cards viable for use both in gaming and in engineering / video work stations.

    I’m not a pro, but do a lot of video editing, rendering and encoding. I’ve avoided dedicating a machine with an expensive special purpose QUADRO video card. Am I reading the wrong thing into this review, or might the new 79XX and the right driver give folks like me the best of both worlds?
  • radojko - Thursday, January 05, 2012 - link

    UVD 3 in NextGen is a disappointing. Nvidia is two generation in front with PureVideo HD 5. Reply
  • psiboy - Monday, January 09, 2012 - link

    Well Mr Ryan Smith I must ask why the omission of 1920 x 1080 in al lbenchmarks... given that almost every new monitor for quite some time has been natively 1920 x 1080... what is it with you guys and Tom's lately.. you both seem to have been ignoring the reality of what most of your readers are using! Reply

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