I have the GTX970 and I play the following games at 1440p, high quality, with zero issue:
Battlefield 3 and 4
Modern Warfare 2 and 3
All of the FEAR series
Far Cry 4
Crysis, Crysis Warhead, Crysis 2, Crysis 3
Black Ops 1, 2 and 3
Serious Sam 3
Wolfenstein New Order and Old Blood
All of them play VERY well. Smooth, high frame rates, no stuttering, etc...
CoD: Infinite Warfare... unplayable. Some scenes are averaging 125fps, while others are a slide show at 7-15fps... Even with the settings turned down... even dropping the resolution to 720p, that game runs like absolute crap half the time and isn't playable, and certainly not enjoyable...
I am looking to upgrade this 970 to a 1070 but don't want to have to mod anything....