dual monitors causes one to turn on and off

[somethingdumb]

hi there guys, i recently replaced several components in my PC, and once I got it all hooked up realized that for whatever reason my second monitor will turn on and off for about 2 seconds every 5-10 seconds, mostly when playing games. This is not an issue i've encountered before and I've found and tried several fixes to no avail.
The second monitor is older, a Hanns-G HW191A connected to a brand new ASUS M5A99X EVO R2.0 via VGA cable to DVI adapter.
The other new components are a Sapphire Radeon NITRO R9 390, an EVGA 700w PSU, and an AMD FX 8350

When ONLY the problem monitor is plugged in (or just the good monitor, some sort of acer), i have experienced no issues. I have tried updating drivers, a more intense overclock, no overclock, and think i have ruled out faulty cables, port or monitor. Again, it almost exclusively happens when gaming and only when both monitors are plugged in. Any ideas? The only think I can think of is potentially a faulty PSU (doubt it) or driver compatibility issues (maybe try older ones?), but i wouldnt even know which drivers to start with. GPU, chipset, an older version of windows 10?

 

[somethingdumb]

update 1: i've now also tried a clean install of the video drivers, also didn't work
update 2: perhaps fairly self evident but it seems like only more graphically intensive games affect the dual monitor setup.
update 3: i've done a full HDD wipe and re-install of windows. everything was working perfectly for a few days and the problem returned suddenly, again while playing overwatch. Any ideas?

 

[bboiprfsr]

Context: it's an old monitor, bud. Dual displays work on my Samsung SMC23A750x and Dell S2340M monitors, but when I add an old 19inch Sony SDM-HS95P monitor that was made in 2005, none of the displays would show.

Bottomline (TLDR): this is probably due to old hardware incompatibility. You need updated monitors to work with updated systems. That's my theory. cheers!

 

[Karadjgne]

That hanns-G hw191a is a 1440x900 LCD monitor. It's new enough tech to handle any gpu. However, the gpu is probably set to 1080p, so what you are getting is resolution conflicts. The hanns might be able to withstand slower fps, such as windows displays etc, but at higher fps it sounds like the monitor just can't keep up. Setting the gpu software to run the hanns at 1440x900 60Hz might solve this. You may also need to fiddle with v-sync, either at the monitor or at the gpu or in-game.