ps help

I bought an second hand rx 570 8GB and when i startgame in fortnite, gpu make one colored screen and then entire system crashes. So i tried furmark and unigine, but gpu went well there, as did half an hour of ethereum mining. I tried underclock memory, core and voltage, but nothing helped. I...

Thoughts? Comments? Muchly appreciated! Based in Australia. Will be adding 2 more fans. http://au.pcpartpicker.com/p/Yy2qxr