Power supply efficiency is without a doubt the most talked about quality in recent years. It's the percentage of current that actually reaches the PC components. If components use a total of 400W, a system with an 80 percent efficient PSU uses 400 / 0.80 = 500W. The same PC with a 90 percent efficient PSU only draws 400 / 0.90 = 444W. It can potentially make a difference in your energy bill, but also translates to other areas. The wasted capacity is turned into heat. The more efficient the PSU, the cooler it stays, the less cooling you need, which improves the lifespan of the components.
The graphs below first show the average effeciency of the tested power supplies, and then the efficiency from 200-1000 watts.
With an average of 89.3 percent the OCZ power supply performs outstanding. The previously tested OCZ Z series 1000 watts was on the same high level. Only the Seasonic 1000 watt PSU with platinum certification is slightly more efficient.