Introduction

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



Cooler Master has thus far included three high-end V units by Seasonic with fully modular cabling designs and four mid-end VSM units featuring semi-modular cabling designs by Enhance Electronics in its portifolio. The company only recently added to their flagship V line with three new V models with capacities ranging from 550 W to 750 W. All of these also feature a fully modular cabling design and a high quality Silencio fan. With the inclusion of these new members, Cooler Master now has a high-end line that covers a wide wattage range. We don't have any information on whether the older VSM (Semi-Modular) units will continue to be available as well, which would give potential buyers a wider range of options to pick from. However, such a move would most likely adversely affect the sales figures of these lower capacity V units, especially if the price difference to their VSM counterparts is as large as it is right now.

Currently, the smallest member of the V line is the V550, which, as its model number implies, has a capacity of 550 W. The PSU features a fully modular design, 80 PLUS Gold efficiency, and a 3D circuit design Cooler Master says to increase efficiency. Given our experience with the VSM550, which leads our low-loads efficiency chart with a huge lead over the competition, we don't have a reason to doubt Cooler Master's statement. All three V units are based on the same platform as their corresponding VSM PSUs, and the only major difference, aside from their fully modular design, seems to be in the 3D circuit design for the secondary side. As we will see in this review, this design actually consists of a PCB that replaces the cables used to transfer power on the modular panel, which minimizes energy losses, especially at higher loads where voltage drops on cables can seriously affect efficiency.

Specifications

Efficiency is 80 PLUS Gold and the maximum operating temperature for around-the-clock operation under full load is only 40°C. Cooler Master should have aimed for 50°C, but probably sought to play it safe. This PSU is obviously Haswell ready since it employs DC-DC converters to generate the minor rails, and installing it will also be a breeze because it uses a fully modular cabling design and is tiny. The V550 is, in fact, one of the smallest fully modular 550 W units available on the market as only SilverStone has similarly sized offerings. The V550 is essentially as big as the VSM550; however, not all the cables of the latter are modular. Cooler Master's V550 also comes with all available protection features, including OTP (Over Temperature Protection).

Cooler Master used a new fan with an LDB bearing, which looks identical to an FDB bearings, operates quietly, and lasts for quite a while. The VSM units use good quality, double-ball bearing fans; however, the Silencio fans with LDB bearings are even better. Although the capacity is low and the PSU's high efficiency could easily allow for it, the V550 doesn't feature a semi-passive operation. Given its fan spins at low speeds at light and mid loads, this is absolutely fine since a passive operation increases operating temperature significantly, which shortens the longevity of such significant components as electrolytic caps. The provided warranty is also quite long at five years; however, Cooler Master's asking price is way too high and should be revised to help with this product's sales figures.


The single +12V rail is strong enough for a moderately strong system with a single VGA, even if it is a high-end one. The minor rails are also strong enough, and the 5VSB rail is as strong as it should be for a low capacity PSU.

Cables & Connectors, Power Distribution

The V550 has enough cables for its category and capacity. While some of you would probably like it to have two pairs of PCIe connectors instead of one, PSUs with a capacity of 550 W are used in single-GPU systems, not stronger gaming stations with SLI or Crossfire configurations. There are two free sockets on the PSU's modular panel, so you could increase the number of PCIe connectors or add an additional EPS connector by purchasing those additional cables seperately.

Cable length is good overall for a mid-capacity PSU, but the 4-pin Molex connectors could afford to be a little further apart. Every connectors also uses 18AWG gauges, which is as the ATX specification recommends.

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

Packaging

At the front of the box is the PSU, on a black backdrop and with its model number and a series of icons for its 80 PLUS Gold certification, five year warranty, Japanese caps, and Silencio fan with an LDB bearing.


The technical specifications and power specifications table are on this side of the box.


On the back is a list of all available connectors, but their length isn't mentioned. Two graphs on the right side depict the fan and efficiency curves. According to the second graph, efficiency drops significantly at higher loads, which we verified in our tests.

Contents

Packing foam surrounds the PSU, offering adequate protection. The PSU has also been put inside a cloth bag.


The bundle includes a set of fixing bolts, the user's manual, several zip ties, and an AC power cord.