AMD's Power Trip: The Radeon HD 6950 and 6970
Now that we’ve seen the feature set, let’s take a look at performance across a variety of games. We’ve tweaked our standard benchmarking list, dropping DiRT2, HAWX and the Far Cry 2 Action benchmarks with F1 2010, HAWX 2 and Metro 2033 respectively. We compared performance against the Nvidia GTX 570 and 580 cards.
It’s worth talking a bit about drivers. Cayman and Barts are new architectures, and drivers are likely still immature. Nvidia’s new GTX 570 and 580 are really the same Fermi architecture we’ve seen for the past year. So it’s likely we’ll see steeper improvements with new drivers for AMD’s new cards over the next few months. However, it’s probably not a wise idea to drop nearly $400 on a graphics cards in the hope that better performance will come later. But that’s been the trend in past releases of new architectures.
Our test bed is a 3.33GHz Core i7-975 Extreme Edition in an Asus P6X58D Premium motherboard with 6GB of DDR3/1333 and an 850TX Corsair PSU. The OS is 64-bit Windows Ultimate. All games are run at 1920x1200 with 4x AA.
Performance Results (DX10)



As we look at three different DirectX 10 games, we can see that the Radeon HD 6970 generally struggles to keep up. While Cayman ekes out a narrow win in Crysis over the GTX 570, it’s 10 fps behind Nvidia’s latest card in Just Cause 2 and falls behind a bit in the Far Cry 2 (Ranch Long) test.
That’s not to say performance is poor, mind you. Performance is actually quite good, but if both cards are in the same price range, the GTX 570 might be a better choice.
Performance Results (DX11)
We’ve emphasized DirectX 11 in this round of benchmarks, because both Nvidia and AMD are touting DX11 performance. AMD’s marketing is pushing the 6000 series as the first of the “second generation” DirectX 11 architectures. Let’s see how the new progeny from AMD’s graphics division fares in a variety of DX11 tests.
Synthetic Benchmarks
First up are a pair of synthetic tests, 3DMark 2011 and Unigine Heaven 2.0. Both are DirectX 11 benchmarks that hammer GPUs, though Unigine tends to focus narrowly on tessellation performance while Futuremark’s 3DMark 2011 pushes a broader DX11 performance envelope.


The heavy tessellation in Heaven’s Extreme mode gives Nvidia’s cards a big edge. But if we look at 3DMark 2011, which uses a wide array of DX11 features, Cayman handles itself pretty well. The HD 6950 is almost a match for the GTX 570, while the HD 6970 beats it by a wide margin. Of course, Nvidia’s pricey GTX 580 continues to rule the single GPU roost.
DX11 Game Benchmark Results
We’ve dropped the older DiRT2 benchmark in favor of the newer F1 2010 test. Interestingly, F1 1010 doesn’t use hardware tessellation. But it does use DirectCompute shaders to accelerated Gaussian blurs for features like lens flares and HDR (high dynamic range) bloom. In addition, the game users HDR lighting using full FP16 floating point formats. F1 2010 also uses additional features in Shader Model 5.0 to achieve better realism using soft shadows.






As we can see, the GTX 570 and the Radeon HD 6970 trade wins, so we’ll call it a wash. If AMD’s intent was to position Cayman against the GTX 570 all along, it looks like that positioning holds mostly in DirectX 11. The Radeon HD 6950 does reasonably well, but it’s clearly a more modest part, as befitting its lower cost.
Power
Let’s take a quick look at power draw. The Radeon HD 6970 has one 8-pin and one 6-pin power connector, while the HD 6950 has two 6-pin connectors.

Despite this, the Radeon HD 6970 still consumes less power – albeit only a small amount -- than Nvidia’s GTX 570 in our full throttle test, while the HD 6950 practically sips power. Idle power draw is pretty much a wash, however, with minimal differences among the two Cayman cards and the GTX 570.
Final Thoughts: Needs Improvement
Cayman looks like an interesting architecture. AMD’s approach of simply “doubling everything” scores some significant performance gains over the HD 6800 series, but seems like an uncharacteristically brute-force approach for a company that’s been priding itself on its focus on efficiency.
That said, Cayman looks to be priced right. The $369 suggested price for online retailers for the reference version is in the same ballpark as Nvidia’s GTX 570, albeit slightly more than Nvidia’s reference price. The HD 6950 is only a little slower, and you may see models under $300, which puts it at about $50 more than a Radeon HD 6870. However, our testing indicates that an HD 6950 is likely to be notably faster in shader-heavy games.
If anything is holding back Cayman, it’s the presence of only 32 ROPs – the same
as the HD 6800s. That means that older games that are more texture effects heavy and use less shader code will likely only be marginally faster than the 6870. But going forward, Cayman is a more robust solution than the 6800s. However, Nvidia still holds the single GPU crown, with the GTX 580. Will AMD’s dual-GPU card, code-named “Antilles”, give AMD the overall performance crown? We’ll just have to wait and see.