I have had a Sapphire R9 290 Tri-X OC for a couple of months now and all of a sudden everything goes to a black screen apparently randomly. Sometimes as soon as the PC starts before I can even put in my password. Often I have to reboot 4-5 times just to start the PC without a black screen! Sometimes as soon as I hit enter to put in my password. Sometimes when playing a game, watching a movie or working. This is definitely the graphics card as this never happens when the card has been removed.