I have a dual screen setup with two AOC e2450Sw monitors connected to a laptop. The laptop has one HDMI and one VGA output. When one of the monitors is connected using VGA, it flickers or displays static noise. The flickering is fairly subtle and only visible on darker colors. But it is there and noticable and appears like horizontal lines.

The problem only appears on the monitor connected to the laptop using the VGA cable. If I swap the monitors, the one connected using VGA is displaying the flicker but not the one connected using HDMI. The simple solution would ofcourse be to connect both monitors using HDMI, but since the laptop only has one VGA and one HDMI out that isn't possible. I've tried tweaking the monitor setting using the OSD menu, but it had little or no effect.

Update: After several more trouble shooting hours, it seems the problem is not related to the monitor or VGA cable as the problem persists even if I swap the display with another brand and different cables. So it may be the graphics card? Intel HD Graphics 4000. The laptop is Acer Aspire E1-571.