Results: BioShock Infinite
Alright, so you get what’s going on now, right? We have average frame rate, divided between what the hardware is cranking out and what you can actually see on-screen, we have both of those frame rates plotted over time, and we have our unique analysis of frame time variance.
Applying the same methodology to BioShock Infinite, the average frame rates once again land fairly close together, despite a frame rate-over-time chart (below) that demonstrates practical frame rates from under 40 to more than 90 FPS.
Fraps would have shown the Radeon HD 7990 in a narrow first-place finish. However, removing dropped and runt frames yields a practical result that falls under what two GeForce GTX 680s and the GTX 690 achieve. The prototype driver helps a little, but not much.
There’s so much going on with this chart that it’s difficult to analyze. Most stark are the dips encountered by Radeon HD 7970 GHz Edition cards in CrossFire, which sharply contrast the two cards’ hardware FPS. When you chart out runts and drops over time, it becomes clear that the 7970s are hammered by the second component of BioShock’s built-in benchmark, which is dominated by runt frames.
The Radeon HD 7990 isn’t subject to nearly as much deviation in hardware and practical frame rate. Two roughly 10-second passages negatively affect the 7990. Otherwise, though, it’s fairly consistent.
Our last puzzle piece puts the Radeon HD 7970s’ behavior into context. Incurring almost twice as much average latency between successive frames, two cards in CrossFire range from about 4 ms up to 24 ms, with outlier spikes as high as 50 ms. Worst-case, the 7990 experiences a similar latency range. But better response to the second sequence in BioShock’s benchmark drives down the average and 75th percentile numbers.
Of course, in comparison, disciplined metering means the GeForce-based solutions offer very similar hardware and practical frame rates.