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
AMD Price NVIDIA
  $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
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  • Ananke - Thursday, December 22, 2011 - link

    "The 7970 leads the 5870 by 50-60% here and in a number of other games"...and as I see it also carries 500-600% of price premium over the 5870.

    Meh, this is so so priced for a FireGL card, but very badly placed for a consumer market. Regardless, CUDA is getting more open meanwhile. AMD is still several generations/years behind in the HPC market and marketing a product above the NVidia price targets will not help AMD to make it popular.

    Having say so, I am using ATI cards for gaming for several years already, and I am very pleased with their IQ and performance. I have always pre-purchased my ATI cards... What I am missing though is teh promised and never materialized consumer level software that can utilize its calculation ability, aka CyberLink and other video transcoders. If it was not for the naughty Nvidia power draw in the 5th series, I would've gone green to have CUDA. Hence, considering SO MUCH MONEY, I am waiting at least 6 months from now to see what the prices will be for the both new contenders in next GPU architectures :).
  • Dangerous_Dave - Thursday, December 22, 2011 - link

    Seems like AMD can't do anything right these days. Bulldozer was designed for a world that doesn't exist, and now we have this new GPU stinking up the place. I'm sorry but @28nm you have double the transistors per area compared with @40nm, yet the performance is only 30% better for a chip that is virtually the same size! It should be at least twice as far ahead of the 6970 as that, even on immature drivers. As it stands, AMD @ 28nm is only just ahead of Nvidia @ 40nm as far as minimums go (the only thing that matters).

    I shudder to think how badly AMD is going to get destroyed when Nvidia release their 28nm GPU.
  • Finally - Friday, December 23, 2011 - link

    I shudder to think how badly one Nvidia fanboy's ego is going to get scratched if team red released a better GPU and his favourite team has nothing to offer.

    Oh... they did?
  • CeriseCogburn - Thursday, March 8, 2012 - link

    We have to let amd "go first" now since they have been so on the brink of bankruptcy collapse for so long that they've had to sell off most of their assets... and refinance by AbuDhabi oil money...
    I think it's nice our laws and global economy puts pressure on the big winners to not utterly crush the underdogs...
    Really, if amd makes another fail it might be the last one before collapse and "restructuring" and frankly not many of us want to see that...
    They already made the "last move" a dying company does and slashed with the ax at their people...
    If the amd fans didn't constantly demand they be given a few dollars off all the time, amd might not be failing - I mean think about it - a near constant loss, because the excessive demand for price vs perf vs the enemy is all the radeon fans claim to care about.
    It would be better for us all if the radeon fans dropped the constant $ complaints and just manned up and supported AMD as real fans, with their pocketbooks... instead of driving their favorite toward bankruptcy and cooked books filled with red ink...
  • Dangerous_Dave - Thursday, December 22, 2011 - link

    On reflection this card is even worse than my initial analysis. For 3.4billion transistors AMD could have done no research at all and simply integrated two 6870s onto a single die (a la 5870 vs 4870) and ramped up the clock speed to somewhere over 1Ghz (since 28nm would have easily allowed that). This would have produced performance similar to a 6990, and far in excess of the 7970.

    Instead we've done a lot of research and spent 4.1billion transistors creating a card that is far worse than a 6990!

    That's the value of AMD's creative thinking.
  • cknobman - Thursday, December 22, 2011 - link

    The sad part is your likely too stupid to realize just how idiotic your post sounds.

    They introduced a new architecture that facilitates much better compute performance as well as giving more gaming performance.

    Did you read the article and look at the compute benchmarks or did you just flip through the game benchmark pages and look at numbers without reading?
  • Zingam - Thursday, December 22, 2011 - link

    Or maybe you just don't realize that they've added another 2 billion transistors for minimal graphics performance increase over the previous generation.

    That's almost as if you buy a new generation BMW that has instead 300 hp, 600hp but is not able to drag a bigger trailer.
    The only benefit for you would be that you can brag that you've just got the most expensive and useless car available.
  • Finally - Friday, December 23, 2011 - link

    Rule 1A:
    The frequency of a car pseudoanalogy to explain a technical concept increases with thread length. This will make many people chuckle, as computer people are rarely knowledgeable about vehicular mechanics.
  • cknobman - Friday, December 23, 2011 - link

    Holy sh!t are you not reading and understanding the article and posts here??????????

    The extra transistors and new architecture were to increase COMPUTE PERFORMANCE as well as graphics.

    Think bigger picture here dude not just games. Think of fusion and how general computing and graphics computing will merge into one.

    This architecture is much bigger than just being a graphics card for games.

    This is AMD's fermi except they did it about 100x better than Nvidia keeping power in check and still having amazing performance.

    Plus your looking at probably beta drivers (heck maybe alpha) so there could very will be another 10+% increase in performance once this thing hit retail shelves and gets some driver improvements.
  • CeriseCogburn - Thursday, March 8, 2012 - link

    I see. So when nvidia did it, it was abandoning gamers for 6 months of ripping away and gnawing plus... but now, since it's amd, amd has done it 100X better... and no abandonment...
    Wow.
    I love hypocrisy in it's full raw and massive form - it's an absolute wonder to behold.

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