Looking at the label on the PSU, the power rating is competitive with other power supplies from 550 to 650 watts. You can draw up to a claimed 50 amps from the 12V rails for a total of 600 watts. This only leaves 31.5 watts for the 3.3 and 5 volt rails, but most entry level enthusiast systems would only require about 50 to 60 watts. This leaves us with about 47 amps available for around 564 Watts.
We also can see that the unit is rated to provide a little extra power, about 80 watts, above the maximum power rating for 60 seconds. It will be interesting to see if the RP650-2 can deliver on this specification. On the downside, there is one item noted in the manual that is of some concern. The power rating assumes operating temperatures of 30°C or less. After that, power output drops to 80% of specified limits at 50°C (about 500 watts). We will certainly look out for this limitation in our hotbox tests.
The most significant feature to note is the Active PFC. Most other power supplies at the Rosewill street price range ($50 to $60 US) will not have this capability. Active PFC makes for a much more stable, efficient power supply since it automatically adjusts to voltage changes. You will notice there is no voltage selector on the PSU. This is a big plus.
Even so, it is not 80 Plus certified, but that does not mean it will not deliver 80 plus efficiency. The manufacturer may have simply opted not to pay for the certification. It will be interesting to see if it makes the grade in spite of no certification.
The other item worthy of noting is the power rating at 50C. The Rosewill specifications were defined at 30C which may or may not be a reasonable operating temperature to expect in many system cases. Our testing will see how important this rating can be.