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.
Facebook
Twitter
RSS
292 Comments
View All Comments
haukionkannel - Thursday, December 22, 2011 - link
Well, 7970 and other GCN based new cards are not so much driver depended as those older radeons. So the improvements are not going to be so great, but surely there will be some! So the gap between 580 or 6970 vs 7970 is going to be wider, but do not expect as big steps as 6970 got via new sets of drivers.Ryan Smith - Thursday, December 22, 2011 - link
This is actually an excellent point. Drivers will still play a big part in performance, but with GCN the shader compiler in particular is now no longer the end all and be all of shader performance as the CUs can do their own scheduling.CeriseCogburn - Thursday, March 8, 2012 - link
I hate to say it but once you implement a 10% IQ cheat, it's though to do it again and get away with it again in stock drivers.I see the 797x has finally got something to control the excessive shimmering... that's about 5 years of fail finally contained...that I've more or less been told to ignore.... until the 100+ gig zip download here... to prove amd has at least finally dealt with one IQ epic fail... (of course all the reviewers claim there are no differences all the time - after pointing out the 10% cheat, then forgetting about it, having the shimmer, then "not noticing it in game" - etc).
I'm just GLAD amd finally did something about that particular one of their problems.
Halleluiah !
Now some PhysX (fine bullet or open cl but for pete sakes nvidia is also ahead on both of those!) and AA working even when cranking it to 4X plus would be great... hopefully their new arch CAN DO.
If I get a couple 7970's am I going to regret it is my question - how much still doesn't work and or is inferior to nvidia... I guess I'll learn to ignore it all.
IceDread - Thursday, December 22, 2011 - link
It's a good card, but for me it's not worth it to upgrade from a 5970 to a 7970. Looks like that would be about the same performance.Scali - Thursday, December 22, 2011 - link
This is exactly the reason why I made Endless City available for Radeons:http://scalibq.wordpress.com/2010/11/25/running-nv...
Could you run it and give some framerate numbers with FRAPS or such?
Boissez - Thursday, December 22, 2011 - link
What many seem to be missing is that it is actually CHEAPER than the current street prices on the 3GB-equiped GTX 580. IOW it offers superior performance, features, thermals, etc. at a lower price than current gen at a lower price.What AMD should do is get a 1.5 GB model out @450$ ASAP.
SlyNine - Thursday, December 22, 2011 - link
Looks like I'll be sticking with my 5870. I upgraded from 2 8800GT's ( that in SLI never functioned quite right because they were hitting over 100C ever with after market HSF) and enjoyed over 2x the performance.When I upgraded from a 1900XT to the 8800GT's same thing, 800XT-1900XT, 9700pro - 800XT, 4200(nvidia)-9700pro. The list goes on to my first Geforce 256 card.
Whats the point, My 5870 is 2! generations behind the 7970 yet this would be the worst $per increase in performance yet. Bummer I really want something to drive a new 120hz monitor, if I ever get one. But then thats kinda dependent on whether or not a single GPU can push it.
Finally - Thursday, December 22, 2011 - link
Since when do top-of-the-line cards give you the best FPS/$?For the last few months the HD6870+HD6850 were leading all those comparisons by quite some margin. The DH7970 will not change that.
SlyNine - Thursday, December 22, 2011 - link
If you read my post, you will notice that I'm compairing it to the improvments I have paid for in the past.40-60% Better than a 2 YO 5870 Is much worse than I have seen so far. Considering that its not just one generation but 2 generations beyond and for 500+$ to boot. This is the worst upgrade for the cost I have seen.....
SlyNine - Thursday, December 22, 2011 - link
The 6870 would not lead the cost per upgrade in performance at all, It would be in the negitives for me.