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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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  • CeriseCogburn - Sunday, March 11, 2012 - link

    We'll have to see if amd "magically changes that number and informs Anand it was wrong like they did concerning their failed recent cpu.... LOL
    That's a whole YEAR of lying to everyone trying to make their cpu look better than it's actual fail, and Anand shamefully chose to announce the number change "with no explanation given by amd"... -
    That's why you should be cautious - we might find out the transistor count is really 33% different a year from now.
    Reply
  • piroroadkill - Thursday, December 22, 2011 - link

    Only disappointing if you:

    a) ignored the entire review
    b) looked at only the chart for noise
    c) have brain damage
    Reply
  • Finally - Thursday, December 22, 2011 - link

    In Eyefinity setups the new generation shines: http://tinyurl.com/bu3wb5c Reply
  • wicko - Thursday, December 22, 2011 - link

    I think the price is disappointing. Everything else is nice though. Reply
  • CeriseCogburn - Sunday, March 11, 2012 - link

    The drivers suck Reply
  • RussianSensation - Thursday, December 22, 2011 - link

    Not necessarily. The other possibility is that being 37% better on average at 1080P (from this Review) over HD6970 for $320 more than an HD6950 2GB that can unlock into a 6970 just isn't impressive enough. That should be d). Reply
  • piroroadkill - Friday, December 23, 2011 - link

    Well, I of course have a 6950 2GB that unlocked, so as far as I'm concerned, that has been THE choice since the launch of the 6950, and still is today.

    But you have to ignore cost at launch, it's always high.
    Reply
  • CeriseCogburn - Thursday, March 08, 2012 - link

    I agree RS, as these amd people are constantly screaming price percentage increase vs performance increase... yet suddenly applying the exact combo they use as a weapon against Nvidia to themselves is forbidden, frowned upon, discounted, and called unfair....
    Worse yet, according to the same its' all Nvidia's fault now - that amd is overpriced through the roof...LOL - I have to laugh.
    Also, the image quality page in the review was so biased toward amd that I thought I was going to puke.
    Amd is geven credit for a "perfect algorythm" that this very website has often and for quite some time declared makes absolutely no real world difference in games - and in fact, this very reviewer admitted the 1+ year long amd failure in this area as soon as they released "the fix" - yet argued everyone else was wrong for the prior year.
    The same thing appears here.
    Today we find out the GTX580 nvidia card has much superior anti-shimmering than all prior amd cards, and that finally, the 7000 high end driver has addressed the terrible amd shimmering....
    Worse yet, the decrepit amd low quality impaired screens are allowed in every bench, with the 10% amd performance cheat this very site outlined them merely stated we hope Nvidia doesn't so this too - then allowed it, since that year plus ago...
    In the case of all the above, I certainly hope the high end 797x cards aren't CHEATING LIKE HECK still.
    For cripe sakes, get the AA stuff going, stop the 10% IQ cheating, and get our bullet physics or pay for PhysX, and stabilize the drivers .... I am sick of seeing praise for cheating and failures - if they are (amd) so great let's GET IT UP TO EQUIVALENCY !
    Wow I'm so mad I don't have a 7970 as supply is short and I want to believe in amd for once... FOR THE LOVE OF GOD DID THEY GET IT RIGHT THIS TIME ?!!?
    Reply
  • slayernine - Thursday, December 22, 2011 - link

    Holy fan boys batman!

    This comment thread reeks of nvidia fans green with jealousy
    Reply
  • Hauk - Thursday, December 22, 2011 - link

    LOL, Wreckage first!

    Love him or hate him, he's got style..
    Reply

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