U4323QE, input lag using PBP from 4 inputs from the same machine (i.e. quadrant display array)

Dell U4323QE has input lag when using PBP from 4 inputs from the same machine (i.e. quadrant display array)

4 inputs from the same PC (Nvidia P1000 with 4 outputs), there is an annoying very noticeable input lag when compared to a single 4K input selected.