Second monitor flickers infrequently with possible behaviour pattern

Hi all,

The problem: My secondary dual-screen monitor constantly flickers infrequently*, and I suspect it's down to what's running on the PC.

*By "constantly flickers infrequently", I mean it doesn't flicker all the time, but when it does begin to flicker it keeps flickering, and isn't dependant on me dragging a window or "doing" something to cause it like many of the troubleshoots I've come across already.

To save confusion I'll reference "Monitor 1" and "Monitor 2" throughout:

Monitor 1 is my MAIN display, and is a ViewSonic VX2453.
Monitor 2 is my SECONDARY display, and is an AOC 22inch Black Widescreen DVI HDCP 60,000:1 DCR 5ms TFT Monitor. This was my old monitor, before purchasing Monitor 1.

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Background Info: I have a custom built PC, inside which is a Sapphire 11199-03-20G HD 7870 2GB GDDR5 OC Graphics Card. This has slots on the back for 1x HDMI and 1x DVI port.

2 years ago when I built this PC, I only had 1 monitor; Monitor 2. This does not have a HDMI port and can only be connected via VGA, therefore it was connected to my GPU's DVI port with the help of a DVI-VGA adaptor.

I later purchased Monitor 1, which has both a VGA and 2x HDMI ports on the back.

In order to use dual-screen, I kept the DVI-VGA (GPU) to VGA (Monitor 2) connection, and bought a HDMI lead to connect my new monitor (HDMI to HDMI; Monitor 1). I made Monitor 1 the primary, and Monitor 2 the secondary, intending to watch videos / read reference materials whilst playing games on Monitor 1.

Both monitors share the same 1920 x 1080 native resolution, and a refresh rate of 60hz. GPU scaling is disabled, and I do not use over/underscanning.

My GPU is not overclocked.

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The problem in some detail: I've not been using this dual monitor setup very often however because it's hurting my eyes.

When my computer is not running any games or programs (just browsers), both monitors appear completely fine, i.e. the picture displayed is constant, without flickering.

When I load a game on Monitor 1 however, Monitor 2 starts to get horizontal lines flickering all the way up and down it. When I close the game, the flickering stops. I've just tried this now with WoW and DayZ, it's not limited to 1 game. Seeing the screen flickering so much either in the corner of my eye when watching Monitor 1, or when watching Monitor 2 directly, cannot be good for my eyes I suspect.

I've noticed that the power button of Monitor 2 is bright orange when it's turned on but not connected to the PC. It used to be like this when it was connected to the PC.

Nowadays, the light goes dim as soon as it receives a picture signal, whether it's as a dual-screen or in use by itself.

The cables used to connect Monitor 2 to the PC, and the GPU in the PC, have not changed since before I bought Monitor 1.

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Some troubleshooting / results:

To eliminate the possibility that the VGA cable is at fault, I have unplugged this from Monitor 2 and placed it in the back of Monitor 1 having removed the HDMI connection from Monitor 1. Due to having no 2nd VGA cable or connection on the GPU, and no HDMI connection on Monitor 2, I cannot dual-screen in this setup, however when playing games with Monitor 1 connected to the GPU by Monitor 2's VGA cable, the picture is crystal clear without flickering.

I have also tried disabling the display of Monitor 1 and transferred it solely to Monitor 2 (like the good old days). When idling, the picture is crystal clear without flickering. Actually, when I play games on it, the same flickering occurs. This didn't used to happen.

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It seems to me, that Monitor 2 is perhaps not getting enough power, hence the dim power light when it receives signal now, and the flickering when anything more taxing than browsers/videos are open?

Monitor 2 is only about 3 years old; surely it can't be on the way out? I'd like to avoid that if possible.

Thanks for all/any help.

 

Given you're ruled out cables, I strongly suspect the problem lies in the second monitor.

My next step would be trying to borrow an extra (known good) monitor for a day or two and hook it up as monitor #2. If you don't get flickering, it indicates your current #2 monitor may have an inverter or internal power problem (which, sadly, means replacing the monitor as having one repaired is usually at or near the cost of buying a new one).

If the borrowed monitor does flicker, it points back to the very remote possibility the video card and/or drivers may have issues.

Hope this helps.