When looking at the Seasonic Power Supply test results we see two values, wattage and volt-amps. Since it might not be clear what they measure, here's a brief overview.

The volt-amp (VA) value is how much real power is being consumed by the power supply being tested to provide the wattage (W) value. The higher the VA value is, the more electricity is being used by the power supply. Because no electrical device is 100% efficient, there will always be some loss when converting AC to DC. The closer the volt-amps and wattage figures are to each other, the more efficient a power supply is. This is called the Power Factor: wattage / volt-amps =PF.

Since we're testing with a 120W dummy load, the load on the power supply (wattage) should be as close to this figure as possible. Anything above this load in apparent power describes the overhead and wasted energy (given off as heat) for the particular power supply being tested. For the unloaded tests, the wattage and volt-amp figures should be as close as possible to one another. The lower the figures are, the less power is being wasted. Measurements were taken with an Extech 380803 Power Analyzer.

Seasonic Power Load Tests Power Supply Model Wattage Test Type Loaded Unloaded Seasonic SuperTornado 400 W (A-PFC) Active Power 177 W 6 W Apparent Power 182 VA 7 VA Vantec iON2 350 W Active Power 192 W 10 W Apparent Power 277 VA 21 VA Antec TruePower 330 330 W Active Power 195 W 22 W Apparent Power 289 VA 38 VA Ultra X-Connect Green UV 500W 500 W Active Power 193W 22 W Apparent Power 307 VA 40 VA AOpen Silent Power AO400-12AHN 400 W Active Power 179W 9 W Apparent Power 275 VA 18 VA Seasonic S12-430 430 W (A-PFC) Active Power 179W 6W Apparent Power 180VA 9VA PC Power and Cooling Turbo-Cool 510 Express/SLI 510 W (A-PFC) Active Power 200 W 29 W Apparent Power 202 VA 32 VA HEC Ace Power 580UB 580 W Active Power 183 W 12 W Apparent Power 272 VA 26 VA HEC Win 550UB 550 W Active Power 184W 10W Apparent Power 263VA 22VA Akasa PowerPlus AK-P550FF 550 W (A-PFC) Active Power 194W 38W Apparent Power 197VA 40VA AOpen Prima Power AO700-12ALN 700 W (A-PFC) Active Power 172W 3W Apparent Power 181VA 9VA PC Power & Cooling Turbo-Cool 1KW 1000 W (A-PFC) Active Power 205W 25W Apparent Power 207VA 32VA Seasonic S12 600 600 W (A-PFC) Active Power 164W 7W Apparent Power 173VA 9VA Mushkin Enhanced XP-650 650 W Active Power 192W 22W Apparent Power 279VA 43VA Seasonic S12 Energy Plus SS-650HT 650 W (A-PFC) Active Power 150W 7W Apparent Power 150VA 10VA Seasonic M12 700W 700 W (A-PFC) Active Power 161W 8W Apparent Power 165VA 11VA Corsair HX620W 620 W (A-PFC) Active Power 171W 8W Apparent Power 173VA 12VA Zalman ZM600-HP 600 W (A-PFC) Active Power 173W 5W Apparent Power 175VA 9VA HEC Zephyr 650 650 W (A-PFC) Active Power 185W 12W Apparent Power 190VA 17VA GlacialPower GP-PS550BP 550 W Active Power 178W 6W Apparent Power 269VA 17VA Cooler Master Real Power Pro 750W 750 W (A-PFC) Active Power 158W 6W Apparent Power 163VA 9VA Seasonic S12 II 500W 500W (A-PFC) Active Power 145W 7W Apparent Power 148VA 10VA Seasonic M12D 750 750W (A-PFC) Active Power 169W 7W Apparent Power 173VA 9VA

The Seasonic M12D 750 power supply drew 169W of power when a 120W load was hooked up, which is about 71% efficiency (at that load). There are a few models we've tested, including Seasonic's recent S12 500W, that have achieved 80% efficiency and higher at the same load. The efficiency of the Seasonic M12D-750 may improve if it was possible for PCSTATS to increase the load conditions closer towards it's rated capacity of 750W. However due to the limitations of our testing equipment we've simplified our test to simulating average load conditions for a normal desktop computer.

Efficient Power Supply Triumphs over Vanity

Seasonic 's M12D 750 is a high-capacity, modular 750W power supply that's aimed at the enthusiast, but still manages to be fairly power efficient.

The Seasonic M12D-750's detachable cabling makes it easy to keep your computer case clean and easy to work inside of. Being able to remove cabling when system components are not in use also improves airflow and lowers ambient system temperatures.

Adding in cables only takes a second, and the cables themselves fit quite snugly and stay in place well. It's a genuinely useful feature to have, and the Seasonic M12D-750 takes it a step further by giving users the options to swap between SATA and four-pin molex connectors.

Having the option to plug in as many as 11 SATA cables or up to eight molex connectors, as well as a quartet of eight-pin (6+2) PCI Express connectors means that this power supply has enough plugs to satisfy even the most extreme power users.

Those who are more concerned about efficiency will be pleased to hear that the Seasonic M12D-750 does quite well. While we were only able to push this system with a 120W load (which is about typical for most desktop systems at idle), it still managed to achieve around 71% efficiency, and maintained steady voltages all the way through our testing. During testing the Seasonic M12D-750 was barely audible, and remained cool to the touch over the duration of it being put under load. The fan itself is automatically controlled by the case temperature, so if your PC isn't under stress or load conditions and building up heat it will remain nicely silent.

On top of that, the 80 PLUS rating, Active Power Factor Correction and Universal AC support are just icing on the cake. For $210 CDN ($180 USD, £110 GBP), the 750W Seasonic M12D-750 power supply offers up great value and handy features that make it worth considering.

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