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Challenging FPS: Testing SLI And CrossFire Using Video Capture

Results: Batman Arkham City

With results to compare in nine games, we're proceeding alphabetically. Batman Arkham Asylum is first in line.

First, we'll look at the minimum and average frame rates. When you see "Hardware FPS" in the charts, you're looking at the number of frames per second the graphics card is rendering. "Practical FPS" is the more accurate representation of what you'd actually see, with dropped frames and runts taken out of the equation.

In addition, we have a fifth data point, captured in Fraps on the CrossFire-based system, to use as a comparison point.

The difference between the hardware and practical frame rates on our GeForce GTX 660 Ti-based SLI setup is only about one frame per second. In comparison, the gap is more like five frames per second on the Radeon HD 7870-based CrossFire configuration.

Fraps would have us believe that the hardware FPS number is right, even though the practical frame rate is lower.

The frame rate over time chart shows us that the Radeon configuration's hardware FPS (the thin red line) and the Fraps result (the thin red line with dots) sometimes spike above the practical FPS (the thick red line). When it comes to the GeForce cards, both lines remain close together.

For reference, we're also including our frame time variance chart, generated from the data generated by FCAT. The GeForce and Radeon cards exhibit sub-10 ms results when we look at the 95th percentile.