Render technique and resolution on Windows 10
The Windows 10 version of Quantum Break uses the same reconstruction method as on Xbox One. If your resolution is set to 1080p, the game temporally reconstructs the image (except UI) from four 720p buffers rendered with 4xMSAA, just like on Xbox One. Engine assigns input geometry samples from 4xMSAA rendering into shaded clusters in order to maximize covered geometry while keeping the performance on acceptable level by reducing expensive shaded samples. When you change the resolution, the buffers used to construct the image are always 2/3rds of the set resolution, i.e. in 2560x1440 they would be 1706x960.
That one weirdest engine i ever heard...