Based on my experience I would say no. I had the Acer XB270HU prior to my x34. While using the Acer XB270HU when playing games like Witcher 3 & Shadow of Mordor I would get an average of 85 fps running at 2560x1440. I'm running 2x EVGA Hybrid 980Ti's in SLI btw. When I switched over to the x34 I thought that because the resolution increased to 3440x1440 that my frame rate would drop but it did not. I still average 85fps in both games. As far as my FPS games I usually stay capped at 100fps which is due to the refresh rate limitations of the x34. When I ran FPS games on the Acer XB270HU I usually hovered around 120-144 fps. I would imagine that if the x34 was able to do 144hz my fps in those FPS games would probably also be about the same. As far as Temps and load they are also running the same as when I was using the Acer XB270HU.
Honestly it doesn't make much sense to me because 3440 vs 2560 is more screen real estate to have to render which you would think would degrade performance but I'm just not seeing it which means if it's there its very very small.
Edited by heyguyslol - 10/30/15 at 7:56pm