Introduction

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

Corsair has grown into a huge company over the last several years, and they are still constantly expanding on all areas they participate in. Especially their PSU portfolio has expanded rapidly lately as we saw Corsair release one line after another, which put the competition into a really uncomfortable position. The fresh RM line is, according to Corsair, optimized for silence, and our experience with the RM750 and RM850 units we already reviewed a while ago confirms just that since both aforementioned units registered very low noise output throughout their entire operating range. We would also like to remind you that the RM750 and RM850 units are made by Chicony while all other RM PSUs are made by Channel Well Technology (CWT), an OEM Corsair has cooperated with successfully for a long time. The RM650 is then based on a different platform than its two bigger siblings, and we are really curious to see how it will perform.

The RM650 is 80 Plus Gold Certified and features a fully modular cabling design, like all RM units. It is also very silent because of its relaxed fan profile and semi-passive mode feature, which only enables the fan when the unit's internal temperature reaches a rather high threshold. The RM650 uses Corsair’s NR135L fan, a custom-design that provides the lowest possible output noise and a near-silent operation at even full speed. We are in a position to confirm Corsair's claim to silence since the same fan is used by all RM units and we have already tested two of them. Another interesting feature of the RM units is their compatibility with the Corsair Link software. However, neither is digital, so only two measurements can be taken through the software: fan speed and current output of the +12V rail. The only downside here is that you have to purchase an additional cable to connect the PSU with a USB header of your mainboard. Corsair apparently didn’t want to further increase the cost of RM PSUs, not even by a few bucks, since Corsair Link only offers two possible readings with this particular PSU.

Specifications

This unit's power output peaks at 715 W for only limited periods of time, usually 60 seconds, while efficiency is officially certified as 80 Plus Gold. The RM650 is also fully modular, Haswell ready, and can deliver its full power continuously at up to 50°C.

Protection features include all those available to a PSU, so both the unit and your system are well protected. The cooling fan uses riffle-bearings to prolong its lifetime, and its semi-passive mode not only lowers noise but also greatly boosts the fan's lifetime, which does, on the other hand, decrease the life of heat-sensitive components, like electrolytic capacitors.

The PSU's dimensions are normal for its capacity, and the same applies to its weight. The RM650 is also compliant with the latest ATX version (2.4), has a pretty long warranty, and its price is on the high side, but we think that the price is justified given its rich feature set.


The single +12V rail can provide the unit's full power alone, which is often the case in PSUs that exploit DC-DC converters for the generation of the minor rails. Speaking of the latter, these are pretty strong at 130 W max combined power, while 5VSB is strong enough with 3 A max current output. As for the -12V rail, who cares for it nowadays? This rail is a remnant of the past, and we really wonder why the newest ATX specification didn't abolish it.

Cables & Connectors, Power Distribution

The number of available connectors is adequate for the capacity of this PSU, however we think that Corsair should offer the option for a second EPS connector even if this would take over a PCIe socket on the modular panel. What we mean is that they should provide an additional EPS cable so the user could have either one EPS and four PCIe connectors at his disposal or two EPS and two PCIe ones, depending on the cables he would chose to use. Regarding cable length it is fine overall, but we would like to see larger distances among the 4 pin Molex connectors, ideally close to 15 cm. Finally, all connectors consist of 18AWG gauges which are the recommended ones by ATX spec.

Since this PSU features a single +12V rail, we have no comments on its power distribution.

Packaging

The box holding the RM650 is much smaller than that of the RM750 and RM850 units, but it features the same design. We find a closeup of the unit's nice fan grill and the model number in large, white and yellow font on the front. Four badges above the model number denote its 80 Plus Gold efficiency, fully modular design, semi-passive mode, and five year warranty.


Only the model number is depicted on this side, along with the "ultra-quiet PSU" description which is 100% true.


This side holds a graphical list of all available connectors, along with useful information about cable length.


Corsair stuffed the most interesting information, including two graphs for the unit's efficiency and the fan's output noise throughout its load range, on the rear. You will also find the power specifications table and several multilingual paragraphs providing a brief description of the unit's most crucial features here.

Contents

As per usual for a Corsair PSU, the package comes with a sleeve. It hides a sturdy cardboard box with Corsair's logo on it. Corsair also opted for more ECO friendly packaging material instead of packing foam this time around. Protecting all parts within well, it is still not as good as packing foam, and the PSU is wrapped in a plastic bag.


The bundle includes the necessary modular cables, a set of fixing bolts, three leaflets, including the user's manual, some zip ties, a case badge, and the AC power cord.