Testing (continued):
The next phase of testing involved using another Seasonic brand tool, a
Power Angel monitoring device that is used to compare various aspects of the AC power going into the power supplies being tested.
The split chart below compares the Power Factor (PF), Amperage (A), Wattage (W), and apparent Wattage (VA) on the test system described on the previous page. We see the same three power supplies under the same three test conditions, this time looking to see how things differed on the AC side of the systems.
The first thing to note is that at this level of loading, the Cooler Master can't quite achieve the rated 0.99 power factor. Increasing the load helps, but if you aren't running close to full capacity you can expect the value to be in the 0.95 range. The next thing we see is that of the three units, the Cooler Master Real Power Pro 1250W Power Supply draws the most current to power the same system. Taking a look at the Wattage and apparent Wattage values shows that the Cooler Master unit is also going to require more voltage than the PC Power and Cooling unit to run in these conditions. While the power required dropped a bit when going from the Enermax unit to the PC Power and Cooling unit, we're back up near the Enermax levels with the Real Power Pro 1250W.
Taking a look at the actual values for my particular situation, and my rate of $0.123210/KWH, allows me to calculate what it would cost to power the "load+" system described with each of these power supplies over the course of one year.
The basic equation is: [KW used] x [price per KWH] x 24 hours/day x 365 days/year.
Cooler Master Real Power Pro 1250W Power Supply's annual cost of operation: $417.70
PC Power and Cooling 750 Quad Black Power Supply's annual cost of operation: $405.82
Enermax Liberty 500W Power Supply's annual cost of operation: $430.65
When you lay it all out it is alot of money, but having a high efficiency unit with a higher power factor rating does help (a bit).
