Review Index:

AMD Radeon HD 7970 3GB Graphics Card Review - Tahiti at 28nm

Author: Ryan Shrout
Manufacturer: AMD

Tessellation, Texture Filtering, Compute Architecture and Media Processing

Along with these compute and architecture changes come quite a few additional performance improvements starting with tessellation.  When NVIDIA introduced Fermi to the world it far exceeded the tessellation performance that AMD offered in their Radeon 5000 series of cards and while both Barts (6800) and Cayman (6900) architectures improved it, NVIDIA still holds a pretty dramatic lead.  

Southern Islands looks to improve on tessellation performance by a factor of 4x while not "wasting die space" as they claim NVIDIA has done.

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The 9th generation tessellation engine from AMD, built inside the dual geometry engines, improves performance with off-chip buffers and slightly larger caches.  The changes AMD has made will improve tessellation at each factor (used to determine tessellation levels) and in many cases, the performance difference is notable. 

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AMD has provided a graph that demonstrates the scaling ability of the new tessellation engine on Southern Islands when compared to the Radeon HD 6970.  Raw tessellation rates have increased from 1.6x to 4x with the majority of the improvement found after a tessellation factor of 9 or 10.  Games and applications that utilize tessellation heavily, like Unigine Heaven, Lost Planet 2 and Crysis 2, see jumps from 55% to 139% in relative performance.

Whether or not this is enough to catch the current generation of GTX 580 designs has yet to be seen though with an obvious improvement in pixel shading power as well (with 2048 SPs), the Radeon HD 7970 will obviously become a performance leader. 

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Being as upfront and honest as they tend to be, AMD discussed their texture filtering quality quite a bit at the technology day in Austin last month.  Improvements in the algorithm have greatly reduced the shimmering artifacts seen on certain textures without having to blur it.  AMD claims that this is all done without any performance penalty and is a result of simple adjustments on their end - no major hardware changes were needed.  

The Southern Islands as a Compute Architecture

Even though AMD was focused nearly completely on the SI architecture as a gaming platform, there is no denying that many of the architectural changes made were the first step in progressing AMD towards a more heterogeneous computing environment.  That is after all, the primary goal of the Fusion System Architecture (FSA) detailed by Demers at AFDS this June.

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SI has a pair of Asynchronous Compute Engines (ACE) that allow for independent scheduling and work dispatch which will improve multi-tasking efficiency and context switching as well.  These engines can operate in parallel with the graphics command processor essentially allowing SI-based parts to work on two varying workloads at the same time.  The matching pair of DMA engines can actually completely saturate a PCI Express 3.0 x16 connection with 16 GB/s of bidirectional bandwidth.

As Josh discussed in his original analysis, AMD has the ability to adjust the ratio of single precision to double precision performance on Southern Islands and for their consumer level graphics cards they have chosen a 4:1 mix.  While the 7970 is capable of 3.79 TFLOPS of compute, it can handle only 947 GFLOPS of double precision.  Because of the move to a vector+scalar architecture though reaching higher utilization of that processing power should be easier for software developers. 

The GPU has full ECC protection for DRAM and SRAM and is the first to offer support for OpenCL 1.2, DirectCompute 11.1 and C++ AMP .

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Finally, rounding out the new architecture changes is an improved media processing feature that improves performance on SADs - sum of absolute differences.  This operation is important for video and image processing algorithms like the one used in AMD's own SteadyVideo technology.  With the Radeon HD 7970 this new QSAD option allows the GPU to handle more than 513 billion calculations per second to keep up with real time playback and adjustment of 1080p 60 FPS content.  AMD claims this performance allows the HD 7970 to operate at a 10x performance improvement compared to the company's own Phenom II X4 980 processor.

December 22, 2011 | 10:29 AM - Posted by Ryan Shrout

Sure man, we'd love to have you write a guest story about the upgrade experience. I am sure quite a few readers will be in the same boat.

December 22, 2011 | 08:56 AM - Posted by Richard (not verified)

I personally think that graphics cards are way overpriced. I will keep my 570 for a good while I suppose. I have a hard time spending more than 350$ especially when you see how games for PC are having problems to run well. Major issues with Battlefield 3, even in the menus, like it is corrupted, image and sound. The beta ran fine which is weird. Will try one more install and if not fixed will have to throw it away, 60$ badly invested. Other games run just fine. Wrote to the company, no reply. By the way, game prices are also way too high in my opinion. Saw Rage for 20$ free delivery at, same game at = 60$ +++ 10$ delivery. That is not right. Waiting for a newegg response...they will not sell to a Canadian on their US site of course.

December 22, 2011 | 10:30 AM - Posted by Ryan Shrout

Not sure about your BF3 issues, sorry to hear.

But yes, I tend to agree - if you have a GTX 570/580 or a Radeon HD 6900 card the difference in performance doesn't warrant the price right now.

December 23, 2011 | 08:36 AM - Posted by Richard (not verified)

Good news, the new drivers seem to have fixed Battlefield.
I gave it a try last night and I got stucked on it for a few hours. Good game by the way, it looks really good on my system. I get a few weird horizontal lines here and there but only in the menu section, strange. Once in the game it runs fine. I play it at 1080p and it is smooth. Happy!!!!!
Thanks for your excellent reviews by the way.

December 23, 2011 | 09:46 AM - Posted by Ryan Shrout

Thanks for reading them Richard!

December 22, 2011 | 09:33 AM - Posted by Shadow (not verified)

This card is not worth the $600 price tag, clearly overpriced in my opinion. And here I thought AMD was the best price to performace PC hardware company, but I guess if you want the first 28nm graphic card you have to pay up. I hope Nvidia comes out with their 600 series soon so the price wars can start on these new graphic cards, but I will be holding onto my EVGA Classified 590 for awhile though. I can play BF3, WOW, and Diablo 3 beta all at high/ultra -1920/1080 settings with no lag or hicups perfectly fine.

December 22, 2011 | 10:31 AM - Posted by Ryan Shrout

True, this is not a replacement for a GTX 590 at all.

December 22, 2011 | 11:57 AM - Posted by Imperfectlink

Looks like a solid showing from AMD. As long as the drivers match the drapes it should do pretty well.

We have to remember that TSMC is having a rough time meeting demand at the 28nm fabrication process so price will reflect that. Signs on the intarwebs point to Kepler lagging behind so why not take advantage of the lead? Bleeding edge has a price and right now it's $550. No doubt AMD will cut the price when yields are good, competition arrives and they can afford to.

December 22, 2011 | 12:51 PM - Posted by Swoosh (not verified)

@ Shadow

Not so fast, this is just a review and AMD is still in the
full authority for the "The last minute say" as far as retail pricing is concerned. For all we know and for what
AMD is known for is that the way they priced their video card products always makes it hard for nVidia to cope up
and compete, this is not just for the video card performance alone BUT for the price to performance ratio
which nVidia are loosing years past since the release of AMD's 5900 series video cards up to now and they may never
regain major market shares unless nVidia would drop their high end video card prices less than to what AMD's pricing
on counterpart models, WHICH will never happen.

Im not saying nVidia video cards are not good but, what AMD
did and currently doing (as we all know) it seems its a one sided race to price to performance ratio and chances are even if nVidia were to release their up coming "not sure
when" 6000 series video cards the same day as AMD's 7900 series video card launch, their prices would be more
expensive and doesnt favor the taste of many gamers now. Another thing that makes nVidia suffer from low sales is the issue of hypocrisy and bad publicity and getting a lot of bad karma on their unfair doings.

AMD for sure will try to make their prices reasonable. Talking about latest technology and hi performance offerings particularly the 7970 model, It is like releasing their 6900 series video cards where gamers have no qualms or issues since day one.

- Very bad for nvidia and its biased bloggers and reviewers.

December 22, 2011 | 01:42 PM - Posted by Anonymous (not verified)

How can I tell if my motherboard supports PCI Express 3.0? It's about 1.5 years old.


December 22, 2011 | 01:59 PM - Posted by Ryan Shrout

It doesn't require a PCIe 3.0 motherboard, PCIe 1.0 and 2.0 are backwards compatible still.

December 22, 2011 | 02:43 PM - Posted by Mechromancer (not verified)

We will finally have an AMD GPU worthy for FOLDING@HOME!!!!!!!!!!!!!!!!!!!!!!!!!

I've waited since the 2900XT for this day. Maybe Stanford will get around to making a good client for it in less than a year this time >:P

December 22, 2011 | 10:23 PM - Posted by nabokovfan87

Heh, and I thought waiting with the 4850 was a long time. Patience is a virtue, well done!

December 23, 2011 | 09:46 AM - Posted by Ryan Shrout

Wow, yah, you are going to see a HUGE performance difference here.

December 22, 2011 | 02:49 PM - Posted by Luzer (not verified)

I have two 5870's in Crossfire connected to three Dell 24"(something like 6080x1200 with bezel compensation on). If I sell both of my cards for ~$300 is it worth the $250 to get a 7970 or should I pick up another 5870 ($150) for triple crossfire or even two 6970's ($300 each)? I can’t really play BF3 with crossfire enabled and using all three displays, av. FPS is around 20 on high, but I can play on a single display, 1900x1200, on high, av. FPS 55, with crossfire.

In the end I probably wait for the 7970 to get down to $375 and put my 5870's in an old pc and use it as a space heater.

December 22, 2011 | 02:57 PM - Posted by JohnE (not verified)

I want to purchase the 6970 MSI Lightning today. I'll be happy with this card as it overclocks to 1ghz stable. When do you think the "older" cards will drop in price? I'm afraid i'll have to wait a month, I WANT MY TOYS NOW! (jk)

December 22, 2011 | 05:36 PM - Posted by Wolvenmoon (not verified)

Will hold on to my 9800GTX+ until prices come down or performance across the board doubles again.

December 23, 2011 | 09:47 AM - Posted by Ryan Shrout


December 24, 2011 | 07:04 AM - Posted by rrr (not verified)

If you have a small monitor, by all means do it.

February 4, 2012 | 07:19 AM - Posted by SiliconDoc (not verified)

I'm holding on to the 9500GT because it rocks out in BF3 at 12-15 fps and that's on a lower end pentium D with 256x4 of 533ddr2 and a 40g ide drive.
Whoo hoo, we iz gamin' !
It doesn't crash, at all, either, unlike the red cards.

December 22, 2011 | 09:04 PM - Posted by Anonymous (not verified)

omg did you test those benchmarks with 0% power control at the CATALYST control center ?. You shoulda test it with +20 power setting, and then try to OC it... you might even get a higher oc since other reviewers get more then 1100mhz out of the core.

December 23, 2011 | 09:47 AM - Posted by Ryan Shrout

We will give that a shot after the holiday.

December 22, 2011 | 10:22 PM - Posted by nabokovfan87

I wonder how the 3 gb Frame buffer affects 3D gaming w/ eyefinity.

December 23, 2011 | 09:48 AM - Posted by Ryan Shrout

It might not help THAT much for 3D as the amount of memory required for 3D isn't much than standard - just processing power. The reasoning: the textures / data need for the left eye are usually a pretty close match to what is needed for the right eye.

December 26, 2011 | 08:56 PM - Posted by nabokovfan87

But doesn't doing 3d require twice as much processing then traditional graphics? For instance, the metro 2033 normal AVG FPS is double what is in 3d. I wonder if the frame buffer would allow more things to be in VRAM or something would happen to give a boost, slight if any. It doesn't seem likely from what you are saying, but it would be something interesting to see.

Especially considering how the 69xx series has had 2 and 1 gb variants and the slight hits in perf. on those cards.

December 23, 2011 | 11:12 AM - Posted by soldierguy

Hey Ryan

Thanks for the review..luv your shows. I've got a pair of 5870 2Gb's in Crossfire powering 5760x1080 and an i7930 oc to 3.8ghz. I'm thinking of a pair of these for my next build or maybe just buying a pair of these and clunking them in the existing unit. Of course money and value are an issue. And would I really see any multi player benefit from just upgrading the gpu's? I guess you'll be doing a comparison against my setup or similar and that would help for sure. But in the real world would there be any "real" improvement in multi player for me. I mostly need the performance for the hi twitch games--for me COD. I play other games too but don't need more computing power for them. Goodluck with the new fiber optics....I'm green with envy..that's where I have problems and limitations.

December 23, 2011 | 01:41 PM - Posted by Mark (not verified)

What I'm getting out of the 7970 is that they realized Nvidia had a superior architecture and mimicked it. Now how this will affect their drivers will be interesting. If anything this equalizes the 2 companies.

Their charging a high premium for cards because they can. Prices will go down SIGNIFICANTLY when Kepler rears its turtle head......TURTLE!!!

Pretty much all this says is that AMD was early this round but Nvidia again will take the performance crown because if they don't surpase a product released 6-9 months prior to theirs then it will not bode well for the green machine.

God I sound like a Nvidia shill....

December 23, 2011 | 02:23 PM - Posted by Davo (not verified)

The prices will go down and quite quickly. AMDs top end cards are cheaper than Nvidia's at present and this series will follow suit.

These cards have a premium at the moment (and we are only speculating at present since they arent yet on sale) but competition amongst AMD resellers will see it go down anyway.

I cant blame them for making hay while the sun shiones at the moment. This card is the top end and represents a small percentage of the overall market and they will sell like hotcakes no matter where they are priced to people who want the top end.

Im happy AMD has at least one division thats actually making great product and competing strongly.

December 24, 2011 | 02:19 PM - Posted by Ryan Shrout

I hope you are right Davo.

February 4, 2012 | 08:45 AM - Posted by SiliconDoc (not verified)

Cheaper by what ? $10 per three hundred, or 3 percent...
Yeah, cheaper by three percent.
$10 bucks is not enough to suffer through the driver issues, the crash issues, the lack of new game support issues, the no PhysX issue...
To all those who've "never had a problem with their radeon cards" congratulations, miracles still do happen.

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