Introduction

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

Eight PSU lines apparently weren’t enough for Corsair, which is why another they say to be situated right below the fresh RM series has been added. According to Corsair, the CS-M line was designed for basic- and mid-range systems; however, it offers features and performance traditionally reserved for higher-end models. They are probably referring to the 80 Plus Gold certification which, although not at the top anymore, is still considered a certification only higher-end, more expensive PSUs feature.

All members of the CS-M series not only feature 80 Plus Gold efficiency, but also compact dimensions and a semi-modular cabling design, two things that will make their installation a breeze in even small cases. A fully modular design would obviously further increase the price, which had Corsair use a hybrid solution instead. Fine with us as long as only the absolute minimum in native cables are included, the CS-M line currently also consists of four members with capacities ranging from 450 W to 750 W.

In this review, we will take a closer look at the CS650M with, as its model number implies, a capacity of 650 W. Its single +12V rail can deliver up to 51 A, which can, along with the four PCIe connectors that equip the PSU, feed two mid-level VGAs for a SLI or Crossfire configuration. The CS650M's price also looks fair for what it offers, but we will put together a clear picture of its price/performance ratio once we finish all testing and have the necessary data in hand to precisely calculate the performance-per-dollar score. When it comes to commercial products like PSUs, the most interesting bit is the performance they offer in relationship to their price, and we really busted our heads to implement an algorithm that effectively calculates the pure performance of a PSU by taking into account all of our test data, but that is another story we already told here.

Specifications

Efficiency is Gold and the PSU isn't only semi-modular but also Haswell ready thanks to the DC-DC converters generating its minor rails. It has all protections except for OCP (Over Current Protection), which is useless in a single-rail PSU of the mid- or high-capacity category.

The cooling fan doesn't feature ball- but sleeved bearings to reduce cost, and at only 14 cm long, the unit is also pretty compact. The warranty is only three years long, which seems very short compared to the five of the RM line, and the unit costs $110.

DC-DC converters are used for the minor rails, yet the +12V rail cannot deliver the unit's full power alone, at least on paper (the +12V rail in a PSU can normally deliver up to 98%-100% of the unit's maximum capacity because it also powers the minor rails). The minor rails have 130 W maximum combined power, which is quite strong, while the 5VSB rail is, with 3 A maximum current output, stronger than usual.

Cables & Connectors, Power Distribution

The PSU has enough connectors for its capacity and cable length is usually adequate. Corsair shortened the gap between SATA connectors since HDDs are normally installed very close to each other, yet all other peripheral devices fed by 4-pin Molex connectors are installed fairly far apart from one another, so a distance a little over 10 cm would be welcome. All connectors use 18AWG gauges, which is as 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 box is rather small, and we find Corsair's specific close-up shot of the fan grill on its face. In the top-right corner and inside a green frame is the series description, and below it are three badges for the 80 Plus Gold certification, three year warranty, and ErP compliance. Right below the aforementioned badges and in big font is the model number.


Only the model number is depicted on this side.


A multilingual list on the bottom of the box includes some of the unit's specifications, and there is a table with all current Corsair PSU lines and their most notable features on the right side.


The rear of the box provides us with a list of all available connectors and cable length numbers, two graphs showing the efficiency and fan noise curves, and a table with this unit's power specifications. There are also three paragraphs elaborating on the CS650M's features.