There are many interesting results at 1080p that we need to discuss. Starting near the top of our graph we see the GTX 780 averages a solid 64fps with a minimum of just 49fps while the R9 290 performs exceptionally well, delivering an average of 70fps and a minimum of just 51fps, arguably being the best value high performance GPU for playing Arkham Knight at 1080p.
The new R9 390 was just a single frame faster than the R9 290 while the R9 390X was just 2fps faster than the R9 290X and both delivered the same minimum frame result. The minimum frame rate seems to be limited by the Core i7-5960X processor, as the GTX 980 Ti would also drop down to just 53fps despite an average of 89fps.
Moving further down the graph we find the GTX 960 delivering playable performance along with the HD 7970 GHz Edition. The old GTX 680 also performed quite well, despite dropping down to 36fps at times.
It was interesting to find that for whatever reason the R9 380 and R9 285 would tank down to just 20fps from an average of 40fps+. They were the only two graphics cards to really drop off like this and the result was extremely stuttery gameplay.