so i have a rx 580 8gb from gigabyte. when i play fortnite it just suddenly shuts off the pc an restarts. i first thought it was a thermal issue so i put up the fan rpm and the gpu stayed at 40-55C.i have tried installing drivers from their website but it still crashes. i tested it 3 times with unigine heaven and it didnt crash. i tried downclocking the memory and the core, and putting the power to - 1,-2,-5,-10. please help any suggestions will be appreciated.