Multi-Card Scaling In Metro 2033
Before we delve too deeply into analysis, let’s talk pricing. For every gap between individual boards, double that when you consider an SLI- or CrossFire-based configuration. That makes it particularly difficult to draw even comparisons. With that said, two GeForce GTX 570s are going to run you a staggering $700. A pair of Radeon HD 6870s go for $480. And if AMD's initial launch pricing plays out on the market, you’re looking at somewhere close to $600 for two 2 GB Radeon HD 6950s and roughly $740 for the 6970s.
At 1680x1050, the Radeon HD 6950s nearly match Nvidia’s more expensive GeForce GTX 570s. The 6970s are faster still, though decidedly not fast enough to justify the hefty price premium you’d pay in excess of the GeForce GTX 570s or Radeon HD 6950s. After all, they don't exactly allow you to step up to a higher resolution than either of the less expensive solutions.
Shifting over to 1920x1200, the 6950s manage to upset the GeForce GTX 570s, in part due to the cards’ larger frame buffers. The gap grows by a frame at 2560x1600, though by this point we’re decidedly no longer getting playable performance.
For the sake of gauging the scaling of this demanding title, we re-ran our benchmarks using a single card at Very High quality settings, 4x MSAA, and 16x AF:
Clearly the Radeon HD 6870’s 1 GB frame buffer prevents it from realizing more than a small bump in performance here. The other cards do wield enough memory to make Metro 2033 a somewhat smoother experience at 2560x1600 and Very High quality settings, though.
The real shocker is that both of the 6900-series cards realize better scaling that Nvidia’s GeForce GTX 570 in SLI.
We explicitly talked to AMD about CrossFire scaling after its press briefing. According to the company, it didn’t make any changes to the Radeon HD 6800 series that would have improved its CrossFire scaling versus the Radeon HD 5870, as many folks suggested in our 6800-series launch coverage. It did, however, incorporate driver-based enhancements that augment CrossFire performance in the 6900 series. This seems to be reflected in the results here.
Now AMD says that the 6800s will get the CrossFire-oriented improvements in a future driver update. For now, though, 5800-series and 6800-series cards should scale comparably, with the 6900s doing even better.