So I'm having a problem with my GPU, the R9 390 Sapphire Nitro unit. I have replaced all the drivers multiple times and all my computers software and BIOS systems are up to date, yet when doing the simplest of task, my computer will black screen, forcing me to hard reboot it. When I turn my computer back on, the Event Viewer hasn't recorded any error messages. I have been trying to troubleshoot this for weeks now and I'm really worried. The box calls for a 850 Watt power supply and that's what I have. When idling, the WattMan view in the Crimson software shows the card will spike in memory from 0-1500 MHz then back in a second. If I leave my computer for a while and come back and move my mouse it crashes sometimes. If I change the WattMan memory settings to go above about 1650 MHz, my computer will instantly crash. I'm just tired of this problem. Is my card bad? Do I not have enough power? Is the card using its memory incorrectly? Please help.