I normally have things running, I use Corsair because I have an HX850i
The game that stressed the crap out of my GPU was Ashes of the Singularity - it used to make my USP beep and thats rated about 450W (APC 800)
On lesser games like Overwatch I draw - 300W
EDIT - I originally had a 390X that's why I was a lot higher in Ashes... now using 580W to reduce Electric draw... my mistake!