Introduction

We would like to thank Cooler Master for supplying the review sample.

The PSU market is a tough one since you can lose the good reputation you build up over many years in a very short time; only a bad or simply not terribly worthwhile PSU line suffices. Cooler Master in fact didn't have a significant presence in especially the high-end PSU categories until a very short while ago since their products utilized older or low to mid-performance platforms. Mostly due to their adhesion to a single OEM, Enhance, and the reluctance to risk picking another OEM that probably would offer them much better platforms to work with, everything changed with the release of the V series putting them back on the map. More and more users are now picking CM PSUs over the high-end competition that ruled this area for quite a long time. But their successful presence in these high-end categories is just the start as the real game is played in lower ones. Both CM's technology and marketing department are aware of these circumstance and have decided to release the GM line, an affordable line for budget-oriented users.

Today, we will test the G550M unit which, as its model number implies, has a capacity of 550 W and exploits a semi-modular cabling design. It is also 80 Plus Bronze certified, has a single +12V rail which, according to CM, can even feed an Nvidia Titan, and is Haswell ready because of the DC-DC converters it uses for the generation of the minor rails. Another very interesting feature of the G550M is its extra-long warranty of five years. The warranty period in this price range usually doesn’t exceed three years, but CM didn’t adhere to those guidelines since they believe in this platform's reliability.

Specifications

Efficiency is Bronze certified, and the PSU only features a few modular cables and is Haswell ready. It also packs all available protections, but CM unfortunately restricted its maximum operating temperature to 40°C, though we will, as per usual, test the unit at higher ambient.

The 120 mm fan uses double ball-bearings, which will increase its lifetime while producing a little bit more noise than a sleeve-bearing fan with similar characteristics. We also think that the fan is too powerful for such a low-capacity PSU, but CM apparently meant to stay on the safe side instead of skirting its edges given that efficiency isn't Platinum or even Gold which will, hence, lead to increased heat dissipation at higher loads. The unit's dimensions are pretty compact and its weight is low, too, and its price looks very good for its characteristics, which will easily boost its price/performance ratio if it performs well in our tests. CM lately follows a very aggressive pricing strategy for their new PSU products, which is to the benefit of all us consumers.


The +12V rail can deliver nearly 50 W less than the total capacity of the unit, which is strange since platforms utilizing DC-DC converters can normally deliver their full power output easily. The minor rails have enough power given the unit's capacity, and the same applies to the 5VSB rail.

Cables & Connectors, Power Distribution

There are enough available connectors for the power characteristics of this PSU; however, a couple more 4-pin Molex connectors would further increase its usability. Also, cable length is good, and the distance among connectors won't pose any problems if you install this unit into a small or medium-sized case. Finally, all connectors use standard 18AWG gauges, the size the ATX spec tends to recommend.

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

Packaging

The PSU comes in a small white package with the unit's photo taking up about half of the front's real estate. Next to it is the model number, depicted in large black font, and below it we find a list with the PSU's most important features, including a series of badges denoting the Bronze efficiency, DC-DC converters for the minor rails, ErP 2013 compliance, single +12V rail, and five year warranty.


This side has the specifications table and a table describing the power specifications of the rails.


A multilingual reference to CM's site for more information about this product is given here, with various certifications this PSU has.



As per usual, the most interesting information is on the back of the box. Here, you will find two graphs showing the efficiency and fan operating curves of the G550M. There is also a short description of the unit's basic features in multiple languages and a photographical list of all available connectors. CM could also add cable length and connector count to provide potential buyers with more juicy information. This may come as hard-to-swallow information, but some people (enough) still decide which PSU they will buy at the last minute, while they are at the store and without reading a review. More information on cable length could come in handy with these fellows. That said, the thriving online shopping culture has reduced last minute purchases while scavenging around a shop, so people do conduct quick searches online before deciding on their choice PSU product.