so i should buy a 750w like I had bought instead of a 850w ?
what can happen if i run my pc with one single gtx 670 and 850w psu for long time ?
im a little bit confused
A psu will operate most efficiently in the middle third of it's range.
It will also run quieter if it does not need to run at max.
Overprovisioning a bit is a good thing.
If anything, it will prolong the life of your psu.