Display problem with E228WFP

The problem shows up when I turn the resolution to 1680x 1050 or 1400x1050. When I look at a full screen of black fonts on white background, I always see that some of the words are darker and unclearer than the others. The unclear words always show up forming a pattern like vertical stripes.. I think there are about 5-6 this kind of stripes on the screen. The words in those stipes appear to be darker an unclear than others. However, when i set down the resolution, the problem is gone.

Do anyone has the same problem???