My XFX Radeo R9 280X GPU recently failed, and I got a replacement card. It seemed to be working fine, but every so often, my screen will go white with moving, flickering, gray/black horizontal lines. This only happens once every day or two, and it requires me to shut down and restart (unplugging and replugging the monitor doesn't work). However, when I shut down, the display returns and the blue "shutting down" Windows screen is displayed, demonstrating that the graphics card can still display clear picture to the monitor. Any ideas about what might cause this? Any help would be appreciated! Thanks!