“We are particularly concerned with efficiency values, an aspect that is frequently overlooked. The more efficient the power supply is, the less energy is converted to heat inside the unit. Less heat means the fans inside the unit spin more slowly while kicking out the same level of power, which translates into significantly less noise. Less heat also means that the components of the supply are under less strain, thus boosting the life of the power supply as well as that of the other components installed inside the computer.”
They have put 21 PSU’s against each other. The Benchmarking results are impressive. There is definately a noticeable difference between some, so definately check out this article before your next PSU purchase.