Faces appear to have an underlying mesh in edit mode Using blender 2.79 here. One of my file has this issue where faces appear to have an underlying mesh in edit mode, even with a freshly added cube. Any clue?
it's looks like Z-culling issue when clipping distance is too big. In this case you may:


Reduce the distance between start and end of clipping (in N-panel):


Try 2.79b or 2.79 master daily build, it have not this problem 
Do not pay attention to it - it is not affects on render.