This is possibly a dumb hack! I have no idea why it works as of now!
So I have this cool Dell S2440L monitor that looks cool. A flat panel of glass, minimalistic design and glossy finish.
I hook it up to my Macbook Pro (2011 edition) through a Mini DP Display Port Thunderbolt To HDMI TV Out Adaptor but I kept facing a flickering problem that is often irritating when using the monitor at a 1080p model. I tinkered with the Refresh Rate but no solution in sight.
I then moved on to tinker with other settings and this setting the resolution to 1600 X 900 seemed to work! My display looks great now and the flickering effort is gone!
Hope this helps! Enjoy! :-)