I just upgraded to an XFX R9 280X on my Gigabyte GA-X79-UD3 with Intel i7 4820K, and I have the issue many other posters have here. Sometimes it sleeps OK, and other times it seems to get stuck between running and sleep. The monitor is sleeping, and I have to force a reboot. Not very convenient for my busy life. Please suggest WORKING solutions only. Thank you.