Well, that's what I've been wondering about because games like Witcher 3, AC Syndicate and GTA V are easily playable for me at 1440p using very decent settings (GTA pushed almost to the max and with .ini tweaks, W3 using a combination of ultra/very high and shadows on low since it doesn't make a difference + SweetFX). In this game, vsync is going crazy and I get frequent drops with not much happening on the screen and I'm not even maxing the game. Sometimes it works good and frames hover around 55-60, and 45-50 during explosions but it feels smooth. Most of the time, though, the game just decides that it prefers to drop into 30s.
All that on a 4790k + GTX 970@1500mhz, so a pretty decent rig. Not immensely powerful but should be well enough for reasonable fps, given that the game's main visual strenghts lie in its artstyle/setting/colours and not technical prowess.