The Nexus 6 is one of the few devices on the market that sports a 1440p “QHD” display. This means that the amount of pixels displayed is higher than almost any other smartphone, which sounds great on the surface, but is not without its drawbacks.
For one, most apps and games are still written with 1080p as their max resolution, since this is the standard amongst current generation devices. And even if an app or game does support 1440p resolution, the graphics processor on your device has to work overtime to track all of those extra pixels, resulting in diminished performance and battery life… more
Sig Nordal 