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
Battlefield 3
Its popularity aside, Battlefield 3 may be the most interesting game in our benchmark suite for a single reason: it’s the first AAA DX10+ game. It’s been 5 years since the launch of the first DX10 GPUs, and 3 whole process node shrinks later we’re finally to the point where games are using DX10’s functionality as a baseline rather than an addition. Not surprisingly BF3 is one of the best looking games in our suite, but as with past Battlefield games that beauty comes with a high performance cost
How to benchmark BF3 is a point of great contention. Our preference is to always stick to the scientific method, which means our tests need to be perfectly repeatable or very, very close. For that reason we’re using an on-rails section of the single player game, Thunder Run, to do our testing. This isn’t the most strenuous part of Battlefield 3 – multiplayer can get much worse – but it’s the most consistent part of the game. In general we’ve found that minimum framerates in multiplayer are about half of the average framerate in Thunder Run, so it’s important to frame your expectations accordingly.
With that out of the way, Battlefield 3 ends up being one of the worst games for the 7970 from a competitive standpoint. It always maintains a lead over the GTX 580, but the greatest lead is only 13% at 2560 without any MSAA, and everywhere else it’s 3-5%. Of course it goes without saying that realistically BF3 is only playable at 1920 (no MSAA) and below on any of the single-GPU cards in this lineup, so unfortunately for AMD it’s the 5% number that’s the most relevant.
Meanwhile compared to the 6970, the 7970’s performance gains are also a bit below average. 2560 and 1920 with MSAA are quite good at 30% and 34% respectively, but at 1920 without MSAA that’s only a 25% gain, which is one of the smaller gaps between the two cards throughout our entire test suite.
The big question of course is why are we only seeing such a limited lead from the 7970 here? BF3 implements a wide array of technologies so it’s hard to say for sure, but there is one thing we know they implement in the engine that only NVIDIA can use: Driver Command Lists, the same “secret sauce” that boosted NVIDIA’s Civilization V performance by so much last year. So it may be that NVIDIA’s DCL support is helping their performance here in BF3, much like it was in Civ V.
But in any case, this is probably the only benchmark that’s really under delivered for the 7970. 5% is still a performance improvement (and we’ll take it any day of the week), but this silences any reasonable hope of being able to use 1920 at Ultra settings with MSAA on a single-GPU card for the time being.
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mczak - Thursday, December 22, 2011 - link
Oh yes _for this test_ certainly 32 ROPs are sufficient (FWIW it uses FP16 render target with alpha blend). But these things have caches (which they'll never hit in the vantage fill test, but certainly not everything will have zero cache hits), and even more important than color output are the z tests ROPs are doing (which also consume bandwidth, but z buffers are highly compressed these days).You can't really say if 32 ROPs are sufficient, nor if they are somehow more efficient judged by this vantage test (as just about ANY card from nvidia or amd hits bandwidth constraints in that particular test long before hitting ROP limits).
Typically it would make sense to scale ROPs along with memory bandwidth, since even while it doesn't need to be as bad as in the color fill test they are indeed a major bandwidth eater. But apparently AMD disagreed and felt 32 ROPs are enough (well for compute that's certainly true...)
cactusdog - Thursday, December 22, 2011 - link
The card looks great, undisputed win for AMD. Fan noise is the only negative, I was hoping for better performance out the new gen cooler but theres always non-reference models for silent gaming.Temps are good too so theres probably room to turn the fan speed down a little.
rimscrimley - Thursday, December 22, 2011 - link
Terrific review. Very excited about the new test. I'm happy this card pushes the envelope, but doesn't make me regret my recent 580 purchase. As long as AMD is producing competitive cards -- and when the price settles on this to parity with the 580, this will be the market winner -- the technology benefits. Cheers!nerfed08 - Thursday, December 22, 2011 - link
Good read. By the way there is a typo in final words.faster and cooler al at once
Anand Lal Shimpi - Thursday, December 22, 2011 - link
Fixed, thank you :)Take care,
Anand
hechacker1 - Thursday, December 22, 2011 - link
I think most telling is the minimum FPS results. The 7970 is 30-45% ahead of the previous generation; in a "worse case" situation were the GPU can't keep up or the program is poorly coded.Of course they are catching up with Nvidia's already pretty good minimum FPS, but I am glad to see the improvement, because nothing is worse than stuttering during a fasted pace FPS. I can live with 60fps, or even 30fps, as long as it's consistent.
So I bet the micro-stutter problem will also be improved in SLI with this architecture.
jgarcows - Thursday, December 22, 2011 - link
While I know the bitcoin craze has died down, I would be interested to see it included in the compute benchmarks. In the past, AMD has consistently outperformed nVidia in bitcoin work, it would also be interesting to see Anandtech's take as to why, and to see if the new architecture changes that.dcollins - Thursday, December 22, 2011 - link
This architecture will most likely be a step backwards in terms of bitcoin mining performance. In the GCN architecture article, Anand mentioned that buteforce hashing was one area where a VLIW style architecture had an advantage over a SIMD based chip. Bitcoin mining is based on algorithms mathematically equivalent to password hashing. With GCN, AMD is changing the very thing that made their card better miners than Nvidia's chips.The old architecture is superior for "pure," mathematically well defined code while GCN is targeted at "messy," more practical and thus widely applicable code.
wifiwolf - Thursday, December 22, 2011 - link
a bit less than expected, but not really an issue:http://www.tomshardware.co.uk/radeon-hd-7970-bench...
dcollins - Thursday, December 22, 2011 - link
You're looking at a 5% increase in performance for a whole new generation with 35% more compute hardware, increased clock speed and increased power consumption: that's not an improvement, it's a regression. I don't fault AMD for this because Bitcoin mining is a very niche use case, but Crossfire 68x0 cards offer much better performance/watt and performance/$.