This is a head-scratcher, for sure. Hoping someone has some insights. I have a 5,1 with a GTX 1080 installed. I recently bought a BenQ monitor, the PD3200. Since day one with this monitor, it will occasionally (once every 1 to 5 minutes) flicker briefly to black. Here is a video demonstrating the problem. I got BenQ to send me a replacement monitor. Still happens. It does not happen when the BenQ monitor is connected to any other system, so it must be the Mac Pro. But I have an LG monitor as well, and it does not happen with this monitor, only the BenQ. It occurs in Boot Camp too. I have tried swapping the 1080 with a flashed 980, the problem still occurs, so it is not the graphics card. I have tried powering the graphics card with an external supply, the problem still occurs, so it is not the power supply. It seems to be a combination of the BenQ monitor and the Mac Pro, but I don't know who to blame. What do you guys think?