haha, 1kw sucks 1kw of power to run your sub 300watts rig.

all your components will blow up and burn down your house and kill your whole family while they're asleep.

even if it's a 1jigawatts flux capacitor PSU, if your rig only draws 300watts max, it'll still use 300watts ONLY!!!.

It has absolutely no affect on your electric bill.