I've purchased an LG 21.5" LED Display with model no. E2250T and I've connected it to my macbook with a mini display to VGA adapter. It work's fine in lower resolutions, but when I choose the best resolution 1920x1020 , display starts flickering randomly and sometimes it goes to power saving mode. I have the same problem with another Monitor-TV (AOC 22") when in high resolution.
The lower resolutions are fine but its not pleasing. Is it the adapter? I'm connecting displays with a VGA cable since I don't have a mini display to DVI adapter. I can purchase that adapter if it solves my problem.