4k@34Hz 4k@36Hz 4k@39Hz 4k@41Hz Or similar fractional refresh rate, but with integer pixel clock. I did not try all of them, but the TV does not seem to like any. "DVI" input port did not help. I am trying to max out HDMI 1.4b (or 1.3) and DisplayPort 1.1.
I tried making BOTH MHz and refresh rates integer with no luck. --- Post Merged, Sep 16, 2016 --- Partial success. The maximum I could do for both HDMI 1.4b and DisplayPort 1.1 was 4k@31Hz. Just by reducing the front porch from 30Hz.