Technically Speaking: At 4K resolution, would there be any improvement to the eye on a recent route between using screen percentage at 150 or having it at 200. I understand that at 200 the GPU is working super hard, but I'm more interested in whether the game would actually look better.
Why not try it for yourself? 4K at 200% means the GPU is rendering 8K images (only advisable on a high end GPU made for 8K), applies TAA and then scales it down to 4K again. Generally speaking, the higher your output resolution, the less need to use upscaling. For HD, I'm using 150% to add the needed subpixels that are needed for TAA interpolation. So just test it yourself.
