AMD Radeon HD 7970 Review: 28nm And Graphics Core Next, Together As One
by Ryan Smith on December 22, 2011 12:00 AM EST- Posted in
- GPUs
- AMD
- Radeon
- ATI
- Radeon HD 7000
Display Tech, Cont: Fast HDMI
Moving on from multi-monitor applications, AMD has not only been working on technologies for multi-monitor users. Southern Islands will also include some video and movie technologies that will be relevant for single and multi-monitor uses alike.
With the 6000 series AMD upgraded their DisplayPort capabilities from DP 1.1 to DP 1.2. With Southern Islands AMD will be upgrading their HDMI capabilities. Currently AMD supports a subset of the complete HDMI 1.4a specification; they can drive S3D displays (the killer feature of 1.4a), but that’s the only thing out of 1.4a they support. HDMI also introduced support for 4K x 2K displays, but both displays and devices that can drive them have been rare. As displays start to become available so too does support for them with AMD’s products.
As per the relevant specifications, both DP 1.2 and HDMI 1.4a can drive 4K x 2K displays, but with the 6000 series the hardware could only handle such a display over DP 1.2. With HDMI it was an issue of bandwidth, as HDMI is based on DVI and uses the same TMDS signaling technology. At normal speed HDMI only has as much bandwidth as single-link HDMI (~4Gbps) which is not enough to drive such a large display. DVI solved this with dual-link DVI, whereas as of HDMI 1.3 the HDMI consortium solved this by tightening their cable specifications to allow for higher clocked transmissions, from 165MHz up to 340MHz.
It’s this higher transmission speed that AMD is adding support for in Southern Islands. AMD calls this Fast HDMI technology, which as near as we can tell is not any kind of HDMI trademark but simply AMD’s branding for high speed HDMI. With Fast HDMI AMD will be able to drive 4K x 2K displays over HDMI – which looks like it will be the common connector for TVs at those high resolutions – along with being able to support 1080P S3D at higher framerates with next-generation TVs. Currently AMD’s cards and TVs alike can only handle 1080P frame packed S3D at up to 48fps (24Hz/eye), or with a bit of hacking up to 60fps (30Hz/eye), which is fine for 24fps movies but much too low for gaming. As next-generation TVs add support for 1080P frame packed S3D at 120fps (60Hz/eye) Southern Islands products will be the first AMD products able to drive them over HDMI through the use of Fast HDMI.
The only remaining questions at this point are just how high does AMD’s Fast HDMI clock (they don’t necessary have to hit 340MHz), and if AMD will add support for any other features that higher bandwidths enable. AMD says that Southern Islands supports “3GHz HDMI”, which appears to be a misnomer similar to how we commonly refer to GDDR5 by its “effective clockspeed” in GHz, even though that’s not actually how it operates. In which case with Fast HDMI AMD may be referring to the maximum throughput per channel, which at 300MHz would be 3Gbps. 300Mhz would still be enough to implement features such as Deep Color (48bpp) over most current resolutions.
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tw99 - Thursday, December 22, 2011 - link
I just wanted to say thank you for including the 8800 GT in some of your benchmark charts. Even though its dated hardware, including it in your comparisons illustrates the punch that the newer hardware has and assists in decision making for people like myself looking to upgrade from their current setup, unlike most benchmarking articles on other sites that like to compare only the very recent generations, not taking consideration what people would have now.Leyawiin - Thursday, December 22, 2011 - link
I wonder if the Arctic Cooling Twin Turbo II I have sitting in the closet (and haven't ever used) would fit on one of these? Its compatible for up to an HD 6970 so I know it can cool one of these sufficiently (if the mounting holes match their old cards). Maybe I should wait to see what the HD 7950 is like - buying the top of the line card at launch usually isn't smart from a value standpoint.Leyawiin - Thursday, December 22, 2011 - link
Its all a moot point anyway. Damn "soft launch" not available for at least three weeks. Just a marketing ploy to keep people from buying Nvidia's top cards at the moment. If you aren't ready to sell your cards, keep your mouth shut.james.jwb - Thursday, December 22, 2011 - link
I have an Arctic Cooling Extreme Plus II on a 6970 and wouldn't use the lower sized versions. But Im also interest to know if it'll fit the 7970. But in all honesty, until these prices come down I won't go near this card, the performance increases just aren't worth it for most people.Dark Man - Thursday, December 22, 2011 - link
It looks like page 7 and 8 got the same content ?Dark Man - Thursday, December 22, 2011 - link
Sorry, page 8 and 9Dark Man - Thursday, December 22, 2011 - link
Page 13 and 14, tooRyan Smith - Thursday, December 22, 2011 - link
We added a couple of pages this morning; you're probably seeing the cascade effect of the rest of the pages being pushed back.evilspoons - Thursday, December 22, 2011 - link
I'd just like to say that I found this review harder to read than the usual stuff on Anandtech. Everything seemed wordy - if there was an opportunity to use a sentence instead of a word, the sentence was used.Good job on the comprehensive information, but trim the fat off the writing next time, please!
RussianSensation - Thursday, December 22, 2011 - link
Even if it's a 6 months lead, 2012 is so far looking like a year full of console ports. We have Syndicate (February 21, 2012), then Mass Effect 3, Max Payne 3 (both on March 6). Those games will get crushed by modern GPUs. HD7970 is an amazing buy for those who are building a new system now/soon and planned to spend $500+ on a GPU. But for current GPU owners, it's not enough of a performance boost imho. And on its own, it's still not fast enough for 2560x1600 either. It's a good card, but since modern GPU generations last 18-24 months, it's too early to call it great.