Yes, I tried the second GPU. And yes, I did game a lot.
I am asking that, so u understand my thinking,
PSU will last long time if u buy your PSU @ max Wattage + 150W extra @ 750W(900)PSU.
It only last so long @ 750W. If u play a lot, it limits the lifetime as it gets hot for long time.
It always has some Watts to spare, but not all brands do that.
Now it could have less than u need.