Flickering horizontal lines

[krzr]

It's not the video card per say. It's the link between it and the monitor. Those are signal inconsistencies.
This usually happens from cables staying too long in the same position and the weight of them affects the connection.

Unplug the monitor cable from the monitor and the video card and plug it back in firmly.
You should notice the "scanlines" disappear completely. Try multiple times until you have it right.

Edit: People think it's the graphics card because they have to remove the cables in order to clean it. Once they plug the cables back and the problem is solved they confirm that it was the graphics card, when actually it wasn't.