Maximum PC: Picking out a power supply is not something that should be taken lightly. In a literal sense, weight is one way to determine if a PSU is up to snuff or not, but you also need to factor in how much wattage you need and how it's distributed -- today's systems rely heavily on the +12V rail(s). The easy way to figure out how much power you need so you don't overspend is to use eXtreme Outer Vision's recently updated online PSU calculator.