Testing – DC Output Voltage Load Regulation
To simulate real world operation, each power supply was connected to the load tester, supplied with 115 VAC, and allowed to burn-in for 24 hrs before voltage readings were taken. In this test we are interested in seeing how well a PSU can maintain the various output voltages while under a moderately heavy load. The DC output voltages were measured with a FLUKE digital multimeter at the ATX connector.
The ATX tolerance for voltages states how much each output (rail) is allowed to fluctuate. Seasonic specifies Â±5% for all outputs except for the -12 V output, which is Â±10%.
The following table lists the DC voltage regulation results for the three Seasonic PSUs.
As you can see, all of the DC outputs were held well within the ATX specification while operating under a 240 watt combined load. The Super Silencer 350 exhibited the best regulation while the larger 460 had the lowest values, especially on the +3.3 VDC rail, but still within spec. All three units produced -12 VDC outputs near the maximum limit (-13.20 VDC) with no load applied. Placing a slight load across the -12 VDC outputs (56 ohm resistor) brought the voltages down closer to their nominal values.
Of particular interest are the three main power rails (+3.3V, +5V and +12V) and the 5VSB line. Maintaining these outputs at optimum levels is important to the reliable operation of any PC. If you push components (overclock/over-volt) then they become even more critical.