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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SlyNine - Friday, December 23, 2011 - link
Are you nuts, the 5870 was nearly 2x as fast in DX 10/9 stuff, not to mention DX11 was way ahead of DX10. Sure the 6970 isn't a great upgrade from a 5870, but neither is the 7970.Questionable Premise
CeriseCogburn - Thursday, March 8, 2012 - link
That happened at the end of 2006 with the G80 Roald. That means AMD and their ATI Radeon aquisition crew are five years plus late to the party.FIVE YEARS LATE.
It's nice to know that what Nvidia did years ago and recently as well is now supported by more people as amd copycats the true leader.
Good deal.
Hauk - Thursday, December 22, 2011 - link
A stunningly comprehensive analysis of this new architecture. This is what sets Anandtech apart from its competition. Kudos Ryan, this is one of your best..eastyy - Thursday, December 22, 2011 - link
its funny though when it comes to new hardware you read these complicated technical jargon and lots of detailed specs about how cards do things different how much more technically complicated and in the end for me all it means is...+15fps and thats about itas soon as a card comes out for say 150 and the games i play become slow and jerky on my 460 then i will upgrade
Mockingbird - Thursday, December 22, 2011 - link
I'd like to see some benchmarks on FX-8150 based system (990fx)piroroadkill - Friday, December 23, 2011 - link
Haha, the irony is that AMD is putting out graphics cards that would be bottlenecked HARDCORE by ANY of their CPUs, overclocked as much as you like.It's kind of tragic...
Pantsu - Friday, December 23, 2011 - link
The performance increase was as expected, at least for me, certainly not for all those who thought this would double performance. Considering AMD had a 389mm^2 chip with Cayman, they weren't going to double the transistor count again. That would've meant the next gen after this would be Nvidia class huge ass chip. So 64% more transistors on a 365mm^2 chip. Looks like transistor density increase took a bit of a hit on 28nm, perhaps because of 384-bit bus? Still I think AMD is doing better than Nvidia when it comes to density.As far as the chip size is concerned, the performance is OK, but I really question whether 32 ROPs is enough on this design. Fermi has 48 ROPs and about a billion transistors less. I think AMD is losing AA performance due to such a skimpy ROP count.
Overall the card is good regardless, but the pricing is indeed steep. I'm sure people will buy it nonetheless, but as a 365mm^2 chip with 3GB GDDR5 I feel like it should be 100$ cheaper than what it is now. I blame lack of competition. It's Nvidia's time to drop the prices. GTX 580 is simply not worth that much compared to what 6950/560Ti are going for these days. And in turn that should drop 7970/50 price.
nadavvadan - Friday, December 23, 2011 - link
Am I really tired, or is:" 3.79TFLOPs, while its FP64 performance is ¼ that at 947MFLOPs"
supposed to be:
" 3.79TFLOPs, while its FP64 performance is ¼ that at 947-G-FLOPs"?
Enjoyed the review as always.
Death666Angel - Friday, December 23, 2011 - link
Now that you have changed the benchmark, would it be possible to publish a .pdf with the relevant settings of each game? I would be very interested to replicate some of the tests with my home system to better compare some results. If it is not too much work that is (and others are interested in this as well). :Dmarc1000 - Friday, December 23, 2011 - link
What about juniper? Could it make it's way to the 7000 series as a 7670 card? Of course, upgraded to GCN, but with same specs as current cards. I guess that at 28nm it would be possible to abandon the pci-e power requirement, making it the go-to card for oem's and low power/noise systems.I would not buy it because I own one now, but I'm looking forward to 7770 or 7870 and their nvidia equivalent. It looks like next year will be a great time to upgrade for who is in the middle cards market.