How would a 6570 work on a 300 watt psu when it requires a minimum of a 400 watt?
A 6770 can run on 400watt psu when it requires a 450watt. It is fact when you are using a powerful cpu or other component that require high power. Minimum psu requirement of gpu is based on core-i7 cpu. So you always dont need recommended psu if you dont have a powerful cpu.