Seasonic G-Series: G-550 Power Supply Review

The Seasonic G Series PSU is here for review in its 550 watt capacity and it looks to be a return to basics for the company with this being basically a "no-frills" unit that has been released without much fanfare. But the basics for Seasonic usually outline what you truly need in a PSU; reliable clean power with a low sound profile.

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Load Testing

For those of you that are curious as to some of the reasoning and equipment behind our PSU testing program here at HardOCP, we have put together a living document that shares a lot of the behind the scenes of the program. The testing we are conducting today is exactly as described in that document and will begin with a range of loads tested at 120v input including our torture test and then move on to the same set of tests at 100v input but without the torture test.

120v Load Testing Results

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Test #1 is equal to approximately 25% of the rated capacity of the Seasonic G-550 at 45c. This makes Test #1 equal to 149W by loading the 12v rail to 10a, the 5v rail to 2a, the 3.3v rail to 1a, the +5vsb to 2a, and the -12v to 0.5a. The results of Test #1 show all the positive DC output rails starting off above nominal with the 12v rail being the furthest above nominal. The efficiency for this unit is starting off rather low actually at 85.52% with an exhaust temperature of 49C.

Test #2 is equal to approximately 50% of the rated capacity of the Seasonic G-550 at 45c. This makes Test #2 equal to 279W by loading the 12v rail to 20a, the 5v rail to 3a, the 3.3v rail to 2a, the +5vsb to 2a, and the -12v to 0.5a. Test #2 sees all of the positive DC output voltages drop, but the largest drop for any rail was just 0.02v. The efficiency has moved up considerably to 88.80% while the exhaust temperature has moved up to 51C.

Test #3 is equal to approximately 75% of the rated capacity of Seasonic G-550 at 45c. This makes Test #3 equal to 408W by loading the 12v rail to 30a, the 5v rail to 4a, the 3.3v rail to 3a, the +5vsb to 2a, and the -12v to 0.5a. Test #3 sees somewhat mixed results when it comes to the changes in the DC output voltages. The 12v rail has dropped by 0.02v, the 5v has dropped by 0.01v, and the 3.3v rail has remained even with Test #2. The efficiency in Test #3 actually moved up from Test #2’s value, as it comes in at 90.97%, while the exhaust temperature has risen to 52C.

Test #4 is equal to approximately 100% of the rated capacity of the Seasonic G-550 at 45c. This makes Test #4 equal to 554W by loading the 12v rail to 41a, the 5v rail to 6a, the 3.3v rail to 4a, the +5vsb to 2a, and the -12v to 0.5a. In the final regular test, we see the 12v rail moves down by the biggest margin so far at 0.04v. The minor rails move down as well, but the peak value is again a small 0.02v. At the same time, the efficiency has only barely dropped to 90.80% with an exhaust temperature of 52C again.

120v Load Testing Summary

The load testing results for the Seasonic G-550 are an easy pass and excellent overall. As we have come to expect from Seasonic the last few years, we see that the voltage regulation is perhaps this unit’s best feature so far. The peak change on the 12v rail over testing was 0.08v and the minor rails, exclusive of the +5vsb, had a peak change of 0.03v. These results are similar to what we saw from the Seasonic X-560 previously. When we come to the efficiency side of things, we see that the unit’s efficiency ranges from 85.52% to 90.97% with a peak exhaust temperature of 52C. Overall, this puts this unit ever so slightly behind the Kingwin LZP-550, and about even with the Seasonic X-560, both which are higher end products than this. Looking at similar products, we see that this unit runs rough shod over the Corsair TX-550M which is the only truly comparable product we have seen recently. All in all, these are excellent results so let’s move on to the 100v testing and see how the unit does there.