I have been having some trouble with my two monitors flicking on and off randomly during the rayCloud stage of processing with Pix4D mapper. This has made it impossible to enter GCPs or perform other activities. After contacting support and providing them with processing information it was determined that the problem was with the video card. I run a NVIDIA Geforce GTX 1050, driver version 399.07, Windows 10, 64 bit, 64 gig ram, CUDA, 1TB SSD machine.
After a trial and error process I found a setting in which the system is completely stable and allows me to go about my processing.
I hope that this may help others!