Monitor or Video Card failing?

[mikestjames]

My secondary monitor is starting to randomly display vertical green bars, which "breathe", or fade in and out to black. Nothing gets rid of them except for a 10-20 minute shutdown. Immediate restart doesn't help. Would you guess it's the monitor failing, or the nVidia GTX660 card? The card is never stressed, runs factory default settings, and runs cool, between 35c & 40c. The secondary monitor is a five-year-old BenQ FP241W, and the primary monitor is a Dell U3014. See image in link.

http://mikestjames.zenfolio.com/img/s8/v82/p1564779247.jpg

Thanks for helping me identify the problem.

 

[Ken g6]

Only on one monitor = probably monitor. Got onboard graphics so you can be sure?

 

[vailr]

Does the faulty monitor use an external power supply? I've seen before, where that can be the source of problems.
Try swapping monitors to better identify which device is having problems.

 

[ArisVer]

Try swapping monitors to better identify which device is having problems.

This.