sentences:  To qualify for 80 Plus, a power supply must achieve at least 80% efficiency at three specified loads (20%, 50% and 100% of maximum rated power).However, 80 Plus supplies may still be less than 80% efficient at lower loads.For instance, an 80 Plus, 520 watt supply could still be 70% or less efficient at 60 watts (a typical idle power for a desktop computer).