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
Portal 2
Portal 2 continues the long and proud tradition of Valve’s in-house Source engine. While Source continues to be a DX9 engine, Valve has continued to upgrade it over the years to improve its quality, and combined with their choice of style you’d have a hard time telling it’s over 7 years old at this point. Consequently Portal 2’s performance does get rather high on high-end cards, but we have ways of fixing that…
Given Portal 2’s wide range of performance it’s possible to at least somewhat bog it down on the GPU side without any special tricks thanks to its heavier use of shaders than in past Valve titles. Given a fast enough card I believe we could hit the 300fps internal Source framerate cap on our testbed, but thankfully at 2560 we’re nowhere close. In any case at 2560 the 7970 is well into the stratosphere, delivering 128.9fps, which is 18% better than the GTX 580. Meanwhile at 1920 as with so many other benchmarks that lead shrinks, this time down to 11%. Meanwhile the 7970 enjoys a smaller lead over the 6970, beating it by only around 30% at either resolution.
The great thing about the Source engine is that it’s well studied, and by utilizing DirectX9 it’s open to a few more image quality enhancements than DX10+ games. We’ve always wanted to have a standard benchmark with more anti-aliasing than just MSAA, and Portal is the perfect candidate. So for the second part of this test, we’ve turned on Super Sample Anti-Aliasing (SSAA) through NVIDIA and AMD’s driver control panels. With SSAA the entire scene gets anti-aliased, going beyond just removing the jaggies at polygon edges and removing all signs of shader aliasing too, making Portal 2 a very good looking game.
As expected, SSAA makes the performance of everything tank. At 2560 the 7970 is well below 60fps, and every other single-GPU card is slower yet. Once we get down to 1920 performance finally reaches a point where it’s playable, as the 7970 reaches 72.2fps.
Compared to its competition, it’s interesting to note that we appear to have hit an entirely different set of bottlenecks by using SSAA. The 7970 leads the GTX 580 by 9% at both resolutions while it leads the 6970 by 25% under the same conditions. We believe that at this point we’re seeing the limitations of ROP performance, which would explain why the 7970’s lead diminishes versus both the GTX 580 and 6970. The additional bandwidth the 7970’s design affords the ROPs can only go so far until it once again becomes a matter of pixel pushing power.
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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.