No its not. Most power supplies have their highest efficiency when operating at 25% to 50% of their max load, and have lowest efficiency when used near its max load.Zenmastur wrote:Buying too large of a power supply is therefore counter-productive since it uses energy less efficiently.
I use a Super Flower Golden King 80+ Platinum 750W for my gaming build, and it has the highest efficiency at 50% load and lowest efficiency at full load. Here is the official testing from 80PLUS itself http://www.plugloadsolutions.com/psu_re ... Report.pdf. Of course you can check other PSU efficiency on the official 80PLUS webpage yourselves.