Black bars on both sides of the screen

recently I've installed Sierra on p5g41t-m lx board with nvidia geforce 210 gpu and 21 inches screen which is 1920x1080*60 Mhz

everything works well and the nvidia drivers are working too expect the display resolution.. it's only works right but with small screen at 1600x1200

i tried 1920x1440 the screen height goes beneath the monitor boundaries but the width is perfect.. but with 1920x1080 the height is perfect but the width has black bars on both sides..