bro, its about your drivers,

install 16.11.2 driver,

if it not fix; try

 first close the automatic ''driver update'' (and also windows update on windows)   (there are videos on youtube about that, its easy)

 download the ''16.11.2'' here:

 http://support.amd.com/en-us/kb-articles/Pages/Radeon-Software-Crimson-Edition-16.11.2-Release-Notes.aspx

16.11.2 is important, do not use timely new drives on rx470 and rx480,


   if it not fix; try

    restart and install DDU, (you can delete the drivers with this program). delete drivers  (close the driver update, (i m not talking about windows update, driver update is a diffrent thing. )   restart and install 16.11.2

   dont change the riser socket position everytime on mobo,