Hey there, this question may have been asked before but I am at witts end about this issue. I have had my RX 580 for a bit over a year now and I initially started having issues about 6 months ago. I started seeing blue and green lines on my primary monitor mainly whilst using Discord and once I moved my cursor over the lines they would disappear. This issue seemed to resolve itself and I have not had the same issue since.
Now however, while gaming, after about 10 minutes of gaming (The Witcher 2, Titanfall 2, Black Desert Online,) Both screens flicker black and then display No signal (Both at the same time) The GPU then throttles and I am still able to hear in game audio and hear voices while on voice chat etc. I have updated my Graphics driver and monitored temps and there are no issues there as the temps are within normal range. My PSU is an old crappy Chinese one that needs replacing but I have never had an issue like this previously until now. One monitor is using a high quality HDMI cable and the other is using a VGA cable. Not sure what is causing this issue but any suggestions would be helpful!