The Corsair HX850 80Plus Platinum PSU

External Appearance

The core aesthetic design of the Corsair HX850 is the same that the company has been using for years for their high-end units. It features a classy, understated design, with a satin black body and all-black cables. The chassis has chamfered edges and decorative stickers cover the largest portion of its sides. Further aesthetic improvements include embossed parallel ridges aligned with the fan’s finger guard wires and a small badge with the unit’s model at the rear side of the chassis. The chassis of the HX850 is 180 mm long, making it significantly longer than a standard ATX unit. This should not be a problem with any modern high-performance ATX case but caution is required with compact and atypical case designs.


Corsair moved the sticker with the unit’s specifications and certifications to the top of the chassis, allowing the user to hide it when the unit is installed with the cooling fan facing upwards. The side stickers are also installed in such a way so that the sticker facing the left panel of the case will always be upright. However, the sticker facing the right panel will always be upside down. Typical cases very rarely have a transparent right side panel but this could be a problem for custom designs. Still, a modder technically can remove and reinstall the side stickers without voiding the unit’s warranty, although keeping the sticker in pristine condition while removing it could prove to be a challenge.


The front of the chassis is littered with the connectors for the modular cables. Aside from the split 18+10 connectors for the 24-pin ATX cable, the rest of the connectors are essentially split into two groups: one group of five PCIe and CPU power connectors and one group of six SATA/Molex connectors. The PCIe and CPU cables share the same connectors on the side of the PSU. There is also a button that allows the user to switch from a single 12V rail mode to a multiple (seven) rail mode. When in multiple rail mode, the HX850 splits the 70.8A 12V output into seven virtual 40A lines, triggering an over-current protection shutdown if a single virtual line is overloaded. This mode provides additional safety and should be used by default, leaving the single rail mode only for competition overclockers or other special applications where a single device could momentarily require over 480 Watts and trigger a safety shutdown.

Packaging and Bundle

Corsair ships the HX850 in a large cardboard box with yellow/black artwork, which is becoming the company’s packaging insignia. The artwork is clean, with the front mainly focused on a picture of the unit itself and a lot of information printed on the sides and rear of the box. Inside the strong cardboard box, we found the unit well protected between thick foam paddings.

Strangely, the bundle of the HX850 is relatively frugal for a PSU of this class. Corsair supplies only the typical AC power cable, black 3M mounting screws, a very thorough multilingual manual, a case badge and a few short cable ties. There are no thumbscrews, cable straps, or other accessories.

The latest version of the HX850 is fully modular, allowing the user to remove even the 24-pin ATX cable. 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 cables are supplied inside a nylon storage pouch. 

Corsair HX850 (CP-9020138)
Connector type Hardwired Modular
ATX 24 Pin - 1
EPS 4+4 Pin - 1
EPS 8 Pin - -
PCI-E 6+2 Pin - 6
PCI-E 8 Pin - -
SATA - 16
Molex - 6
Floppy - 1


Introduction, Internal Inspection Cold Test Results (Room Temperature)
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  • LordanSS - Tuesday, October 24, 2017 - link

    If I remember correctly, Corsair markets the RM series as their "silent option" for PSUs. There's a couple reviews of RMs here in Anandtech.
  • jonnyGURU - Monday, October 30, 2017 - link

    No. Really, the two difference between RMx and HX is that RMx is Gold and has a rifle bearing fan while the HX has Platinum efficiency and a Protechnic (patented) FDB fan. Otherwise, the platform is the same and the components are 97% similar.

    AX does NOT feature anything digital. Only AXi does.
  • lazarpandar - Tuesday, October 31, 2017 - link

    Can 850w power 2x1080ti + OC Ryzen 1700?
  • FaaR - Wednesday, November 1, 2017 - link

    You probably could, but it would be stressing your PSU relatively close to its full capacity. Components live longer and run more efficiently if they're not pushed so hard.

    My system is an i9-7900X and 2x R9 390X GPUs powered by a Corsair RM1000i, and when everything runs full tilt power draw can reach 750W+.
  • lazarpandar - Friday, November 3, 2017 - link

    thank you
  • bluewaffles - Monday, November 20, 2017 - link

    Blue Waffles is a new health problem that is going viral with many Women and Men fearing that they have the infectious disease. Many memes and trolls are also being created where a user sends a file named Blue Waffles and the receiver

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