AMD's Radeon HD 6970 & Radeon HD 6950: Paving The Future For AMD
by Ryan Smith on December 15, 2010 12:01 AM ESTMeet the 6970 & 6950
Now that we’ve finally looked at what makes the 6900 series tick, let’s look at the cards themselves.
If you’re familiar with the 6800 series, then the 6900 series is nearly identical. For our reference cards AMD is using the same style they used for the 6800 cards, utilizing a completely shrouded and squared off design. Furthermore unlike the 5800 series AMD is utilizing the same cooler/PCB/layout for both the 6970 and 6950, meaning virtually everything we have to say about one card applies to the other as well. In this case we’ll be using the 6970 as our point of reference.
Top: 5870. Bottom: 6970
Starting with the length, the 6970 measures a hair over 10.5”, giving it the same length as the 5870. Buyers looking for a 5850-like shorter card will have to look elsewhere else for the moment, as the 6950 is the same 10.5”. Power is provided by a set of 6+8pin PCIe power sockets at the top of the card, necessary as the 6970’s 250W TDP is in excess of the 225W 6+6 limit. The 6950 on the other hand does use 6+6 PCIe power sockets in the same location, afforded by its lower 200W TDP.
Cracking open the 6970 we find the PCB with the Cayman GPU at the center in all its 389mm2 glory. Around it are 8 2Gb Hynix GDDR5 chips, rated for 6Gbps, 0.5Gbps higher than what the card actually runs at. As we’ve said before the hardest part about using GDDR5 at high speeds is the complexity of building a good memory bus, and this continues to be the case here. AMD has made progress on getting GDDR5 speeds up to 5.5Gbps primarily through better PCB designs, but it looks like hitting 6Gbps and beyond is going to be impractical, at least for a 256bit bus design. Ultimately GDDR5 was supposed to top out at 7Gbps, but with the troubles both AMD and NVIDIA have had, we don’t expect anyone will ever reach it.
Moving on to the cooling apparatus, vapor chamber coolers are clearly in vogue this year. AMD already used a vapor chamber last year on the dual-GPU 5970, while this year both AMD and NVIDIA are using them on their high-end single-GPU products. Compared to a more traditional heatpipe cooler, a vapor chamber cooler is both more efficient than a heatpipe cooler and easier to build in to a design as there’s no need to worry about where to route the heatpipes. Meanwhile airflow is provided by a blower at the rear of the card; compared to the 5870 the blower on the 6970 is just a bit bigger, a fair consideration given that the 6970 is a hotter card. Interestingly in spite of the higher TDP AMD has still been able to hold on to the half-height exhaust port at the front of the card.
As for I/O we’re looking at AMD’s new port layout as seen on the 6800 series: 2x DVI, 1x HDMI 1.4, and 2x mini-DP. All together the 6970 can drive up to 6 monitors through the use of the mini-DP ports and a MST hub. Compared to the 5800 series the DVI-type ports have a few more restrictions however; along with the usual limitation of only being able to drive 2 DVI-type monitors at once, AMD has reduced the 2nd DVI port to a single-link port (although it maintains the dual-link pin configuration), so you won’t be able to drive 2 2560 or 3D monitors using DVI ports.
Elsewhere the card features 2 CrossFire connectors at the top, allowing for tri-CF for the particularly rich and crazy. Next to the CF connectors you’ll find AMD’s not-so-secret switch, which controls the cards’ switchable BIOSes. The card has 2 BIOSes, which can be changed with the flick of a switch. The primary purpose of this switch is to offer a backup BIOS in case of a failed BIOS flash, as it’s possible to boot the card with the secondary BIOS and then switch back to the primary BIOS after the computer has started in order to reflash it. Normally AMD doesn’t strike us as very supportive of BIOS flashing, so this is an interesting change.
The BIOS Switch
Like the 5870 the back side is covered with a metal plate, and while there aren’t any components on the back side of the card to protect, this is a nice touch by making it easier to grab the card without needing to worry about coming in contact with a pointy contact.
Finally, while the card’s overall dimensions are practically identical to the 5870, we noticed that the boxy design isn’t doing AMD any favors when it comes to CrossFire mode with 2 cards right next to each other. The 5870’s shroud actually jutted out just a bit at the center, keeping the ventilation hole for the blower from pressing right up against the back of another card. The 6970 does not have this luxury, meaning it’s possible to practically seal the upper card depending on how you screw the cards down. As a result our CF temperatures run high, but not to a troublesome degree. We’d still encourage AMD to take a page from NVIDIA’s book and to bring the shroud in a bit around the blower so that it has more room to breathe, particularly as their TDP is approaching NVIDIA’s. In the meantime we’d definitely suggest spacing your cards apart if you have a motherboard and case that allows it.
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versesuvius - Friday, December 17, 2010 - link
Ananke,I am not very knowledgeable about this, but I don't think a modern GPU can fit inside a CPU for now. A better idea would be a console on a card. The motherboards on the consoles are not much bigger than the large graphic cards of today. A console card for $100 would be great. I am sure that there is no technical obstacles that the average electronic wizard cannot overcome, doing that.
Sure, there is a use for everything. I can imagine that every single human being on earth can find a use for a Ferrari, but the point is that even those who do have it, do not use it as often as their other car, (Toyota, VW or whatever). In fact, there is rarely a Ferrari that has more than 20,000 km on it, and even that is put on it by successive owners, not one. The average total an ordinary person can stand a Ferrari is 5000 KM. (Disclaimer: I do not have one. I only read something to that effect somewhere). Having said that, I do have a sense of the "need for speed". I can remember sitting in front of the university's 80286 waiting for the FE program to spit out the results, one node at a time, click, click, ... . You have millions of polygons, we can have billions of mesh nodes, and that even does not even begin to model a running faucet. How's that for the need for speed. I do appreciate the current speeds. However, the CPU deal was and is a straight one. The graphic card deals, today, are not. To be clear, the "and" in "High End"s and "Fool"s is an inclusive one. "Someone will pay for it", was also initiated in the eighties of the last century. By the way, the big question "can it play crysis", will no longer be. Crysis 2 is coming to the consoles.
Quidam67 - Friday, December 17, 2010 - link
"But can it play Crysis" should be in the Urban dictionary as a satirical reference on graphics code that combines two potent attributes: 1) is way ahead of its time in terms of what current hardware can support 2) is so badly written and optimised that even hardware that should be able to run it still can't.In 1000 years time when Organic Graphics cards that you can plug into your head still can't run it smoothly @2560*1600 60fps they will realise the joke was on us and that the code itself was written to run more and more needless loops in order to overwhelm any amount of compute-resource thrown at it.
Iketh - Friday, December 24, 2010 - link
LOLmarc1000 - Friday, December 17, 2010 - link
I swear I've read ALL the comments to see if anyone already pointed it... but no one did.I feel a bit disappointed with this launch too (I have a 5770 and wanted to get 6950 but was wanting a bigger increase %-wise). But one thing interesting it the number of Stream Processors in the new gpus. By the "pure processor" count this number decreased from 1600 SPs on 5870 to 1536 SPs on 6970. But the size of the VLIW processors changed too. It was 5 SPs on 5870 and now is 4 SPs.
So we have:
hd5870 = 1600 SPs / 5 = 320 "processors"
hd6970 = 1536 SPs / 4 = 384 "processors"
if we take that 384 and multiply by 5, we would have 1920 SPs on the new generation (on par with many rumors). this is 20% more shaders. and considering AMD is saying that the new VLIW4 is 10% faster than VLIW5 we should have more than 20% increase in all situations. but this is only true in the minority of tests (like crysis at 2560x1660 where it is 24%, but in the same game at 1680x1050 the increase is only 16%). and at the same time the minimun FPS got better, yet in another games the difference is smaller.
but then again, I was expecting a little more. I believe the 6950 will be a worthy upgrade to me, but the expectations were so high that too much people ended a little disappointed... myself included.
Sunburn74 - Tuesday, December 28, 2010 - link
Well... at least they delivered on time and didn't make you wait 6 more months to simply deliver an equivalent, if not considerably worse, product.Mr Perfect - Friday, December 17, 2010 - link
Yes, the minimums are appreciated when they're included.It would be even better if the framerates was displayed as a line graph instead of a bar graph. That way readers could tell if an average consisted of a lot of high peaks and low valleys, or really was a nice smooth experience all the way through. Some other review sites use linegraphs and while I visit Anandtech for it's timeliness, professionalism, industry insight and community involvement, I go to the other sites for the actual performance numbers.
Quidam67 - Friday, December 17, 2010 - link
There is further rationale for splitting the article. Lets say someone is googling "HD 6970 architecture" perhaps they will pick up this review, or perhaps they won't, but either way, if they see that it is actually a review on the cards, they might be inclined to bypass it in favour of a more focused piece.And again, there is no reason why the Architecture Article can't provide a hyperlink to the review, if the reader then decides they want to see how that architecture translates into performance on the current generation of cards supporting it.
I really hope AT are reading this and giving it some consideration. As you say, they are a great sight and no one is disputing that, but it's not a religion, so you should be allowed to question it without being accused of blasphemy :O)
dustcrusher - Friday, December 17, 2010 - link
It really comes down to how important the mainstream market is. If they are a large enough segment of the market, one company using a simple, easy-to-grasp naming convention would likely grab some market share. Make it easy to buy your product and at least some people will be more likely to do so.If not, then it's fun to talk about but not terribly important. Tech-savvy folk will buy whatever meets their needs price/performance-wise after doing research, even if a card is named the Transylvania 6-9000 or the Wankermeister GTFO. Eager to please tech-naive folk are going to buy the largest model number they can get with the money they have, because "larger model numbers = bigger/better equipment" is a long-established consumer shorthand.
I have a half-baked idea for a model numbering system that's based around the key specs of the card- it's a 5 digit system where the first digit is the hardware platform ID (like what we have now, mostly) and the other four would represent combinations of other specs (one digit could be the lowest memory clock speed and bus width would be 1, the next lowest memory clock speed and lowest bus width would be 2, etc).
No idea if this could actually be implemented- there are probably too many variables with GPU/memory clock speeds, among other things.
Shinobi_III - Saturday, December 18, 2010 - link
If you ever saw Nvidia 4xAA in action, you know it's not as smooth as the radeon implementation (especially in motion) and z-buffer miscalculations has always been a nvidia feature.Go up a hill in Fallout New Vegas and look at Vegas in the horizon, with Nvidia cards it always looks like a disco due to meshes overlapping. Now do the same on Radeon.
TheUsual - Saturday, December 18, 2010 - link
Right now, Newegg has a 6870 for $200 after rebate. Two of these makes for an awesome value at $400. The top tier of cards doesn't give a corresponding increase in performance for the extra cost. Two 6950s costs 50% more but does not give you 50% more FPS. Two GTX 460 1GBs is also a great bang for the buck at $300.Neither of these lets you do triple SLI/XFIRE however. That would be what would be paying extra for.
My hope is that the price will drop on the 6950 by around February. By then the GTX 560 should be out and might drive prices down some. The benchmarks could change some with Sandy Bridge too, if they are currently CPU bound.