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Seasonic G-Series 550W PSU preview: affordable Gold power supply

80 Plus Gold power supplies are known for not being the most affordable, particularly if they have a sticker with the name Seasonic on them. Their new G series is supposed to be more affordable, and Hardware.Info tested the Seasonic G-series 550 Watt.

That PSU is currently available for £80, making it one of the more affordable 80 Plus Gold power supplies you can find. The distributor informed us they are planning to make it even more affordable, which would make this a truly great bargain.

The Seasonic G-series 550 Watt power supply has a single 12V rail with a maximum capacity of 45A. That means that the power supply can fulfil almost its total capacity (540 Watts) on the important 12V rail. It's a modular PSU with 5x molex, 6x Serial ATA and 2x 6/8-pin PEG connectors. The motherboard cable is nicely sleeved, but the others are just plain black so they also look fine. The power supply has a single 12cm fan, the speed of which depends on the load.

Its dimensions are modest, with a depth of 16cm. The 1.8kg PSU comes with a five-year factory warranty.

For testing power supplies we utilise professional Stratron load generators, which allow us to put a load of up to 1600 Watts on PSUs in our test lab. We test each PSU in increments of 100 Watts up to the maximum load. At each step we measure voltages on the different lines. The closer those measurements are to the official values of 3.3, 5 and 12V, the better. More than a five per cent deviation is not good.

At each step we also measure the current from the socket with a professional Zes Zimmer ammeter. Based on this we calculate the efficiency. An oscilloscope allows us to measure the ripple, which are fluctuations in the direct current (dc) output of a power supply which has been derived from an alternating current (ac) source. Read the rest of Seasonic G-Series 550W PSU preview on (opens in new tab).