The majority of power supplies available today are rated as Gold or Platinum by 80 Plus. While these numbers aren’t foolproof indicators of quality, they can tell you whether a PSU is better than average (which is what matters). Platinum-rated PSUs deliver up to 90% efficiency at 50% load. Gold units match that rating at 20% load. If you have an energy-efficient system with an overclocked CPU and multiple graphics cards, it may be worth spending extra on a platinum unit. Otherwise, gold should do just fine.