The performance we recieved when running the built-in benchmark suggested that Batman: Arkham Knight played well on mid-range to lower-end hardware and this simply wasn't what gamers have been reporting. Hoping to shine a light on the issue, we tested the most demanding aspect of the game (driving around in the Batmobile) using Fraps and here are the results.
Using the exact same setting when running the built-in benchmark we see a different story when driving the Batmobile around. There is a clear bottleneck at 1080p which limits all cards to between 30 and 34fps for the minimum frame rate. You won't often see just 3fps separating the R9 280X from the GTX 980 Ti when comparing minimum frame rates.
The averages weren't much better as the GTX 980 Ti was just 6fps faster than the R9 280X. There is clearly something in the game limiting performance when driving the Batmobile.
Still, it is important to note that all GPUs above delivered perfectly playable performance in Arkham Knight at 1080p.
Increasing the resolution to 1440p didn't have much of a negative impact on performance, certainly not as you would expect. Again the high-end GPUs are limited to around 30fps with an average of around 40fps.
At 4K we start to see a reduction in performance when comparing 1440p and 1080p. The GTX 980 Ti was still able to deliver playable performance while the GTX 980 started to feel laggy.