I've had this problem and I can't figure out the cause of the problem. I have tried connecting with VGA and HDMI, I've also connected to on-board video as well as the discrete GPU. The effect is not always present and doesn't always appear in the same way. It seems to grab pixels from one place and flicker them in the same area of the monitor. It seems to appear a lot when watching videos and on websites. It seems that I can cause it to happen more by typing or moving the mouse over links. I was thinking it could be the monitor, but if that was the case I would expect it to be more consistent like stuck or dead pixels. I found a video on YouTube of someone that had issues with the flicker of a certain shade of gray. Adjusting the colors slightly in NVIDIA fixed the issue for him. It is also strange that I can capture the pixel flicker by pressing 'print screen' This issue has been bothering me for many months and I would love to resolve it. After taking the first screen shot of the flicker I was unsuccessful in taking more. They can grab the pixels from the the current window or a window behind it. I'm at a loss in regards to this issue.