Corsair may today be one of the largest companies in the PC market, offering literally hundreds of products, but that was not always the case. The company started off as a manufacturer of memory-related computer products and took them many years to even consider diversifying into other segments of the market. Their first significant diversification attempt away from RAM-related products was towards the power supply unit (PSU) market, with the company initially releasing just a couple of PSUs. That move was a great success for the company and the beginning of Corsair's expansion towards multiple segments of the PC market.

Although the company today produces hundreds of products, they still place a significant amount of attention on their power supply products, with Corsair having not only one of the largest selection of products but excellent reputation in the field as well. The company today markets dozens of PSUs through nine different product series. In today's review, we are testing a unit of their most popular series, the RMx.

Corsair initially released the RM series several years ago, with the products designed to be reliable, quiet, and to offer good overall performance, yet still affordable. More recently, the company added some new features that bifurcated the series in two, giving birth to the RMi and RMx series. With the former, Corsair added software monitoring and control to the RM series, a feature that was previously reserved only for the premium HXi and AXi units, however the added features did come at the cost of higher prices. On the other hand, the RMx series is true to the original vision of the family, consisting of quality modular PSUs that are primarily designed to offer good overall performance and quiet operation. The unit that we are reviewing today is the latest (2018) revision of the RM850x.

Power specifications ( Rated @ 50 °C )
AC INPUT 100 - 240 VAC, 50 - 60 Hz
RAIL +3.3V +5V +12V +5Vsb -12V
MAX OUTPUT 25A 25A 70.8A 3A 0.8A
150W 850W 15W 9.6W

Packaging and Bundle

We received the RM850x in a large cardboard box with the yellow-black artwork that is becoming the company's color theme. The front of the packaging is clean, focused on a picture of the unit itself and noting its output and only the most important features. Detailed information about the unit and its performance can be found on the sides and rear of the box. Inside the box we found the PSU protected inside thick foam paddings and packed inside a synthetic cloth pouch.

The bundle of the RM850x is simple and straightforward, which is not something unexpected for a product of this class. We received a typical AC power cable, four black M3.5 mounting screws, a thorough manual that is printed in 10 languages, a case badge and a few short cable ties. Corsair does not include thumbscrews, cable straps, or other accessories with this PSU.

Like its previous version, the RM850x is fully modular, meaning that even the always-necessary 24-pin ATX cable is removable. The SATA and Molex cables are flat, ribbon-like, but the larger PCIe and ATX/EPS power cables are normal round cables with black nylon sleeving. The designer could not use ribbon-like wires for everything because small filtering capacitors are hidden inside the sleeving of the larger cables. The cables are supplied inside a nylon storage pouch. No cable straps are supplied here either, Corsair is using simple wire ties.

Corsair RM850x (2018)
Connector type Hardwired Modular
ATX 24 Pin - 1
EPS 4+4 Pin - 2
EPS 8 Pin - -
PCI-E 6+2 Pin - 6
PCI-E 8 Pin - -
SATA - 10
Molex - 8
Floppy - 1
The Corsair RM850x (2018) PSU
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  • philehidiot - Thursday, August 23, 2018 - link

    Just wondering, if anyone is reading this, how do you ensure the PSU is safe / fully discharged before you crack open the case? I'd hate to be on the receiving end of those primary caps discharging. As would the 16 electrodes in my thoracic spine. As would the lithium battery pack implanted in my back....
  • Calin - Sunday, August 26, 2018 - link

    You might disconnect the power cord and push the start button. Or wait until all the LEDs inside are no longer lighting up.
  • Barrade - Wednesday, September 12, 2018 - link

    Anyone else have issues with the quality of their plastic sheathed cables? I've had to RMA an entire PSU due to the 24pin being malformed & having too much wobble in general. The PSU's themselves have been decent, however I feel they skimped on the cable quality & tollerance.
  • JasonMZW20 - Wednesday, October 31, 2018 - link

    Mine are okay on the previous RM850x. My only complaint is the spliced dual 6+2 pin PCIe connectors, but they work just the same.

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