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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nitro912gr - Thursday, December 22, 2011 - link
I was planning a switch from AMD (4850) to a(n) nVidia GPU for my next upgrade, because they perform well both in computing and in gaming, and I need both fields to be filled here.But now I'm not sure about that, I will wait a bit to see how the software will welcome the new architecture first.
I hope they work as well so I can just pick the cheapest GPU.
Chloiber - Thursday, December 22, 2011 - link
The thing I still don't like about the new AMD cards is their massive problems with anisotropic filtering. AMD promised twice (with Cayman and Tahiti) that the "AF-Bug" is gone. But it's still mediocre to NV and worse than older cards (pre-R600).The bad thing about this is, that it's easily detectable in games and not just a theoretical flaw. It got better than Cayman, but it's still worse than NVs AF.
CeriseCogburn - Thursday, March 8, 2012 - link
Yes, thank you for that. We are supposed to ignore all amd radeon issues and failures and less thans, though, so we can extoll the greatness....Then when they "finally catch up to nvidia years later with some fix", the reviewers can tell us and admit openly that amd radeon has a years long problem of inferiority to nvidia that they "finally solved" and then we can get a gigantic zipped up download to show what "was for years amd fail hidden and not spoken of" is gone !
Hurrah !
Wow it's so much fun seeing it happen, again.
KoVaR - Thursday, December 22, 2011 - link
Awesome job on power consumption and noise levels. If only AMD did so well in the CPU realm...alpha754293 - Thursday, December 22, 2011 - link
Can you play a game while running a compute job?There's word that even for the nVidia Tesla compute accelerators (based on Fermi) that it stutters when you try to play a game or video while it is actively computing/working on something else.
Is that the case here too?
SlyNine - Thursday, December 22, 2011 - link
I'm sure it does, Context switching still occures a huge penalty.MrSpadge - Thursday, December 22, 2011 - link
GCN won't be able to help this on its own. The software needs to catch up. It's a major concern for true GP-GPU and heterogenous computing, though! And not even just launching a game, trying to use your desktop is enough of a problem already..MrS
shin0bi272 - Thursday, December 22, 2011 - link
Id really like to see is when you guys bench with an nvidia physx game... run the bench with physx on (maxed out if there's an option) once and off once.I know everyone is going to claim that physx is a gimmick but a good portion of that reason is because when a game supports it NO ONE BENCHMARKS IT WITH IT ON! That's like buying a big screen tv and covering half of it with duct tape. And lets not forget AMD opted to not use the tech when nvidia offered it to them... so AMD's loss is Nvidia's gain and no one uses it in their reviews because its not hardware neutral. That's partial favoritism IMHO.
Also why wasnt the gtx590 or the 6990 tested @ 16x10 dx10 HQ 16xaf on Metro2033? The 580 was tested and the 6970 were but not the dual chip cards. Whats up with that?
Finally - Thursday, December 22, 2011 - link
Spoken like a true Nvidia viral marketing shillshin0bi272 - Friday, December 23, 2011 - link
So because I prefer the extra eye candy physx offers I cant ask a question about a testing methodology? Sounds like someone has physx envy.