The rating of a power supply (gold, silver, etc... ) is a measure of how efficient it is. A higher rating means less electricity is lost to heat. It has nothing to do with the wattage. This is a gross generalization but, for most people, 500 or 600 watts is more than enough. Why even get 750w if you don't need it? A little extra never hurts and the additional cost is very small. This is a great deal for a 750w PS and I plan to get one for the next system I am building.