AnandTech has taken a look at 12 power supplies in the 500-550W range. You can check it out over here.
Last month, we reviewed 20 power supplies ranging from 300W to 450W. These are great for entry-level or even midrange systems, with optimal efficiency typically falling in the 100W to 200W range. Today, we have 12 more power supplies on our test bench, this time targeting a slightly higher range of 500W to 550W. This particular sector is where we really start to see higher quality designs and better technologies, in part because these tend to be more expensive PSUs.
The best units in the test were the Tagan SuperRock, Arctic Cooling Fusion and BFG LS-550.