I have this GPU since 1-2 year and had never any problem. Since about 1 week have black screen after random time, during i play(its games that i play since 2-3 Years, mostly Strategygames like HOI4 or EU4). More information and stuff that i try so far :
-I check temperatures, its about 60-70 Celsius.
-Upgrade any possible stuff "AFTER" i begin to get black screens. OS, GPU Driver etc.(i always upgrade manuell...never change runnig system )
-I didn´t change any thing. Not new program, not new Hardware.
-Never overcloack GPU or CPU
My system :
Sapphire R9 390 NITRO 8 MB
12 GB Ram
Win 10 Pro 64bit