Are you using a display port cable? If yes, is it vesa certified? If no, I'd suggest you buy a vesa certified display port cable as non vesa certified display port cables can cause black screens. 
 
To obtain the latest vbios you'll need to contact evga support... https://www.evga.com/about/contactus/ 
 

 
Source: https://s3.amazonaws.com/download-aws.futuremark.com/3dmark-technical-guide.pdf
 
So to pass the 3dmark stress test you want to set your gpu fan speed to 100% as it will help keep your cards clocks more consistent which in turn will keep your average frame rate more stable as well.