I see horizontal lines moving down my screen?

[TheHogDog]

When I am playing a game, I see horizontal lines moving down my second monitor. Main monitor using HDMI and my second monitor is using one cable VGA to DVI-I. I don't think that it happens when I use a VGA/VGA into a DVI adaptor then into my GPU.
Is there a difference between that? Why is it possibly that a one cable VGA to DVI-I is causing these lines on my second monitor when gaming

 

[hang-the-9]

Don't use the cable then, not all of them work well. If not using it makes the issue go away, the fix is simple, as is figuring out the cause. Could just be a cheap cable that can't handle the bandwidth of the signal, poor shielding, bad connector somewhere, bunch of reasons as to exactly why it's doing it.