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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mac2j - Wednesday, December 15, 2010 - link
Um - if you have the money for a 580 ... pick up another $80-100 and get 2 x 6950 - you'll get nearly the best possible performance on the market at a similar cost.Also I agree that Nvidia will push the 580 price down as much as possible... the problem is that if you believe all of the admittedly "unofficial" breakdowns ... it costs Nvidia 1.5-2x as much to make a 580 as it costs AMD to make a 6970.
So its hard to be sure how far Nvidia can push down the price on the 580 before it ceases to become profitable - my guess is they'll focus on making a 565 type card which has almost 570 performance but for a manufacturing cost closer to what a 460 runs them.
fausto412 - Wednesday, December 15, 2010 - link
yeah. AMD let us down on this here product. We see what gtx580 is and what 6970 is...i would say if you planning to spend 500...the gtx580 is worth it.truepurple - Wednesday, December 15, 2010 - link
"support for color correction in linear space"What does that mean?
Ryan Smith - Wednesday, December 15, 2010 - link
There are two common ways to represent color, linear and gamma.Linear: Used for rendering an image. More generally linear has a simple, fixed relationship between X and Y, such that if you drew the relationship it would be a straight line. A linear system is easy to work with because of the simple relationship.
Gamma: Used for final display purposes. It's a non-linear colorspace that was originally used because CRTs are inherently non-linear devices. If you drew out the relationship, it would be a curved line. The 5000 series is unable to apply color correction in linear space and has to apply it in gamma space, which for the purposes of color correction is not as accurate.
IceDread - Wednesday, December 15, 2010 - link
Yet again we do not get to see hd 5970 in crossfire despite it being a single card! Is this an nvidia site?Anyway, for those of you who do want to see those results, here is a link to a professional Swedish site!
http://www.sweclockers.com/recension/13175-amd-rad...
Maybe there is some google translation available or so if you want to understand more than the charts shows.
medi01 - Wednesday, December 15, 2010 - link
Wow, 5970 in crossfire consumes less than 580 in SLI.http://www.sweclockers.com/recension/13175-amd-rad...
ggathagan - Wednesday, December 15, 2010 - link
Absolutely!!!There's no way on God's green earth that Anandtech doesn't currently have a pair of 5970's on hand, so that MUST be the reason.
I'll go talk to Anand and Ryan right now!!!!
Oh, wait, they're on a conference call with Huang Jen-Hsun.....
I'd like to note that I do not believe Anadtech ever did a test of two 5970's, so it's somewhat difficult to supply non-existent into any review.
Ryan did a single card test in November 2009.That is the only review I've found of any 5970's on the site.
vectorm12 - Wednesday, December 15, 2010 - link
I was not aware of the fact that the 32nm process had been canned completely and was still expecting the 6970 to blow the 580 out of the water.Although we can't possibly know and are unlikely to ever find out what cayman at 32nm would have performed like I suspect AMD had to give up a good chunk of performance to fit it on the 389mm^2 40nm die.
This really makes my choice easy as I'll pickup another cheap 5870 and run my system in CF.
I think I'll be able to live with the performance until the refreshed cayman/next gen GPUs are ready for prime time.
Ryan: I'd really like to see what ighashgpu can do with the new 6970 cards though. Although you produce a few GPGPU charts I feel like none of them really represent the real "number-crunching" performance of the 6970/6950.
Ivan has already posted his analysis in his blog and it seems like the change from LWIV5 to LWIV4 made a negligible impact at the most. However I'd really love to see ighashgpu included in future GPU tests to test new GPUs and architectures.
Thanks for the site and keep up the work guys!
slagar - Wednesday, December 15, 2010 - link
Gaming seems to be in the process of bursting its own bubble. Graphics of games isn't keeping up with the hardware (unless you cound gaming on 6 monitors) because most developers are still targeting consoles with much older technology.Consoles won't upgrade for a few more years, and even then, I'm wondering how far we are from "the final console generation". Visual improvements in graphics are becoming quite incremental, so it's harder to "wow" consumers into buying your product, and the costs for developers is increasing, so it's becoming harder for developers to meet these standards. Tools will always improve and make things easier and more streamlined over time I suppose, but still... it's going to be an interesting decade ahead of us :)
darckhart - Wednesday, December 15, 2010 - link
that's not entirely true. the hardware now allows not only insanely high resolutions, but it also lets those of us with more stringent IQ requirements (large custom texture mods, SSAA modes, etc) to run at acceptable framerates at high res in intense action spots.