Custom Resolution for LG monitor

I am trying to find the correct custom resolution for my LG 4k monitor. I a using a AMD m6000 video card. Was working at 3840x2160 but had to reload windows and lost the settings. I tried serval settings but I get a screen that is to large (no task bar) and fuzzy. I confirmed that in windows display the setting for enlarging text/apps is set at 100%.

Suggestions please