Introduction

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



The G series is currently Seasonic’s second most affordable series after the S12G line. It includes four members with capacities ranging from 450 W to 750 W. Some of you will remember our G-550 model review only to wonder what the point in testing the unit again would be. The reason is simple as Seasonic recently silently upgraded some of their G series units, terminated the 360 W model, and introduced a new 750 W model. A quick look at the model numbers and all its crucial specifications shows that those remained the same. The only noticeable difference is the Haswell compatibility badge on the package itself, which doesn't mean much since the older units featured DC-DC converters and were Haswell ready. Seasonic simply sought to highlight the fact and took the opportunity to do so to make a few internal changes we will detail in the following pages.

The G-550 unit we will evaluate today is 80 Plus Gold certified, features a semi-modular cabling design, and is pretty compact. It also uses a ball-bearings fan, which will last longer, and doesn’t include a semi-passive operation, which is contrary to the high-end Seasonic units that go fanless at low loads. This PSU is essentially destined for a mid-range system with a single VGA or two low-end ones because it only comes with two PCIe connectors and relatively low capacity. We know that four PCIe connectors can often be too much for a 550 W unit if you, for example, try to feed two AMD R9 280X VGAS, but anything less should run so long as you don't overlock anything. However, Seasonic made a point of playing it safe in order to avoid situations where a user might try to run a configuration not meant to be run by a 550 W PSU. Judging by the performance of the previous G-550 model, our expectations are high for its new iteration, but we will have to wait for our test results to see whether those expectations will be met.

Specifications

Like with the previous model, efficiency is 80 Plus Gold certified, and the G-550 is Haswell ready and can deliver its full load continuously at up to 50°C. It also packs all available protection features, and its cooling fan uses ball-bearings, which increase its life-cycle.

As you can see in the above table, its dimensions are pretty compact as it is only 16 cm length, and the unit comes with a long five year warranty. The price looks very good for the PSU's specifications.

The single +12V rail can deliver nearly the PSU's full power alone, while the minor rails are 100 W strong combined, which is enough for a contemporary system and a PSU of this capacity. The 5VSB rail has the typical amperage for a modern, low- to mid-capacity PSU.

Cables & Connectors, Power Distribution

Seasonic unfortunately didn't increase the number of PCIe connectors with their new G-550 model, so its owners will only have a pair of them at their disposal. This is a mid-capacity unit of high caliber, so it could support two mid-level VGAs with two PCIe sockets each. We strongly believe that Seasonic's conservative policy highly restricts this PSU's usability, but the company probably means to push users that need more PCIe connectors toward stronger Seasonic units to keep everything on the safe side. The number of other cables and connectors is good for the unit's capacity, but we object to the length of its EPS cable. The aforementioned cable should normally at least be 60 cm long; however, its short length will actually be beneficial if you install this unit into a small case. Both SATA and 4-pin Molex connectors come with cables of different lengths, with the shorter cables well-suited to smaller cases. All connectors also use 18AWG gauges, which is the size the ATX spec recommends.

Since this PSU features a single +12V rail, we do not have anything to comment on about its power distribution.

Packaging

The package is exactly the same as that of the previous G-550 unit, with the only noticeable difference the Haswell-ready icon right next to the 80 Plus Gold badge. This icon is a fast and easy way to distinguish the previous G-550 unit from the new one.


On this side is a photo of the PSU, its badge for Gold efficiency, and a QR code you can scan with your smartphone so long as you have the appropriate application installed.


Here are two tables that list the units technical and power specifications. One of the two labels at the bottom depicts the product's serial number, which you will need in case of an RMA.


A series of icons on the rear of the box depict the unit's features. The most crucial of these include its Gold efficiency, the polymer and high-quality electrolytic capacitors used, the DC-DC converters, and its modular cables.

Contents

Two layers of packing foam inside the box protect the PSU well. Next to the PSU is a cloth bag with all the accessories.


A pretty rich bundle for such an affordable PSU, it includes several Velcro straps, some zip ties, a reusable cable tie, an AC power cord, the user's manual, a set of screws, and a case badge.