Things like the FPS of a game and framepacing are down to the One X, A new monitor wont fix that... how the fps works is the gpu of the One X sends a frame to the monitor so many times a second. The monitor will display those frames if they are within the refresh range. If they are over the refresh range you are likely to not notice it, but if they are under you will see framerate dips cause by the Xbox not outputting the frames in the correct intervals. When a large explosion or something demanding happens in a game this causes the CPU/GPU to hit the redline which in turn will slow down the process of sending frames as all resources with be used up. In short a monitor will not fix this... The problem of frame drops is between the software(game) and hardware running the software(Xbox One X).