The Real Power Pro 1250 is one of 10 power supplies receiving nVidia's highest SLI rating, for three 8800 Ultras or 8800 GTXs. It also has an 80Plus certification, certified to maintain more than 80% efficiency. Actually, this power supply is rated up to 87% efficiency. What does that mean? A more efficient power supply uses less wall current than a less efficient one, which means less dollars out of your pocket.