Basically I want to build a very low power PC for file serving so I can stop using my power hungry 4ghz i7 920 and I was wondering how important is it to get a higher 80 plus rated psu? As far as newegg is concerned there is only one Platinum rated PSU and the markup in price is $30~ versus a gold rating with equal wattage. Really just wondering if it would be noticeable on a powerbill over the course of 1-2 years.