I don't know who the oem is that made it,but this 650watt model is a multirail while the 750 a single rail is.This is of no real consequence for the reliability of the psu and it also has a 10 year warranty so imo should you be fine with the 650watt.
Maybe that the
Power Supply Master knows which oem it is that made the 650watt evga.
For the 10 years of warranty do you need to register,
This product comes with a 10 year limited warranty with registration within 30 days of purchase.
Maybe they just revamped the old model from fsp but that's guessing on basis of the similar specs,only reviews will show that to me.