Seasonic G Series 550 W Review 22

Seasonic G Series 550 W Review



We would like to thank Seasonic for supplying the review sample.

Such hard times demand a good understanding of the market, and Seasonic apparently hit a jackpot with their new G series that consists of budget oriented PSUs promising high performance and efficiency with a five year warranty. The fresh G series consists of four members with capacities ranging from 360 W to 650 W. All feature Gold capacity, a single +12V rail, ball-bearing fans, and high-temperature-rating electrolytic capacitors. All are based on modern platforms. Every G series PSU, with the exception of the smallest one, also utilizes a semi-modular cabling design with flat modular cables.

It is, without any doubt, very nice to see top-notch OEMs like Seasonic offering higher-end platforms for user-friendly prices. The capacities of the G series units may look low to some users, but hardly any system actually needs more than a 500-600W PSU. Just take a look at the power consumption page of one of W1zzard's reviews and check how much power a modern graphics card, without any doubt the most energy consuming component in a system, eats. That is, if you think a system actually requires a stronger PSU.

"The stronger, the better" rule doesn't really apply to PSUs. The best option is to get a PSU strong enough to handle your system's power consumption. That way you will have the best possible efficiency at typical loads. Besides, the money you will save on electricity will also protect the environment by lowering your energy consumption and carbon footprint. It is better to get yourself a low to middle capacity PSU that matches your system if you are not a hard-core overclocker with three to four graphics cards under the hood.


Seasonic SSR-550RM Features & Specs
Max. DC Output550W
Efficiency80 PLUS Gold
Operating temperature0°C - 50°C
ProtectionsOver Voltage Protection
Under Voltage Protection
Over Current Protection
Over Power Protection
Over Temperature Protection
Short Circuit Protection
Cooling120 mm Double Ball-Bearing Fan
Dimensions150 mm (W) x 86 mm (H) x 160 mm (D)
Weight1.8 kg
ComplianceATX12V v2.31, EPS 2.92
Warranty5 years
Price at time of review (exc. VAT)$99.99

This PSU's efficiency is Gold, its capacity is medium, and it is, as the ATX spec recommends, able to operate at 50°C. All available protection features for desktop PSUs, including the essential Over Temperature Protection (OTP), are present inside the G-550.
The fan that cools down the unit has a 120mm diameter and is equipped with ball-bearings for increased lifespan. The G-550 has normal dimensions for its capacity and will easily fit in every chassis that takes ATX PSUs. Finally, the provided warranty is set at five years, which is a pretty long period. The G-550, although it is considered cheap for a Gold Seasonic PSU, still meets some strong competition from, mainly, Rosewill Capstone units because of its price-tag.

Seasonic SSR-550RM Power Specs
Max. Power20A20A45A2.5A0.3A
Total Max. Power550W

There is only one +12V rail that can output almost the unit's full power, which is really convenient for contemporary systems that draw most power from this rail. The minor rails are set at 100 W max combined, which is a sufficient power level for a medium capacity PSU. The 5VSB rail can deliver the standard 2.5 A; the minimum current output we meet in today's PSUs at this rail.

Cables & Connectors, Power Distribution

Native Cables
ATX connector (540mm)20+4 pin
4+4 pin EPS12V/ATX12V (540mm)1
Modular Cables
6+2 pin PCIe (600mm )2
SATA (390mm+110mm+110mm+110mm)4
SATA (300mm+110mm)2
4 pin Molex (410mm+125mm+125mm)3
4 pin Molex (305mm+125mm) 2
FDD adapter (+110mm)1

The main downside of the G-550 is the existence of only two PCIe connectors which greatly restricts the PSU's usability. We think that Seasonic should provide the G-550 with four PCIe connectors in order to be able to support two GPUs with dual-power connectors each. On the other hand, they probably didn't want to create internal competition with their X-560 unit that features two PCIe connectors as well. Since the PCIe cables are modular, the addition of two more connectors is a relatively easy process that would only increase the cost of the PSU slightly while, at the same time, highly increasing its usability. The unit does, thankfully, come with enough SATA and peripheral connectors for its capacity.
As the above table shows, there are only two native cables. The EPS cable is relatively short and could cause trouble in a large, full-tower chassis, but a large chassis is usually intended for high-end systems with lots of components, and the G-550 wouldn't suit such a system even if it had a longer EPS cable. The SATA and peripheral cables come in two sets. One has more connectors with a longer distance up to the first connector, and one has fewer connectors on a shorter cable. This is very convenient and will make cable-management tasks easier. Finally, all connectors use 18AWG gauges which is, according to the ATX spec, the minimum requirement for the primary rails.

We do not have anything to comment on about its power distribution because this PSU feature a single +12 V rail.


The new G-550 comes in a nice white package with a simple but charming graphic. In the top left corner, we find Seasonic's name/logo and the series description with the unit's capacity above that. The Gold efficiency badge takes the bottom right corner.

On one of the two sides is a photo of the unit while the other side has the specifications table. The top side doesn't include any noteworthy information.

On the rear side, Seasonic lists all the crucial features of the PSU in an intuitive way. The most important are its Gold efficiency, the modular cabling system, the DC-DC converters for the generation of the minor rails, the good quality caps (both electrolytic and polymer ones), and, of course, the provided five year warranty.

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