I have recently built a mining rig with 7x GTX 1070s, and I am mining Ethereum. I am having an issue where one of the cards is causing the drivers to crash, and every once in a while, the system will boot and show 6/7 cards. When this happens, it becomes stable. This makes me think one of the PCI risers is failing, however, I don't know how I can easily and safely single out which one it is. The fans on the GPU's are all running, it's not as easy as spotting the one with no fans on. How can I identify which one is the culprit within the OS?