Corsair HX850 PSU Review

Early Verdict

The HX850 is a high performance power supply, offering a dead silent operation under all conditions. For the moment its main competitors are the EVGA 850 G3 and the Seasonic FOCUS PLUS Gold and Platinum units with 850W capacity. None of those though manages to match the silent operation that the HX850 offers. Corsair did a stunning job in this section.


  • +

    Full power at 46°C

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    Ripple suppression

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    Full protection features set

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    Load regulation

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    Hold-up time

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    Accurate Power Ok signal

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    Build quality

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    Fully modular

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    2x EPS & 6x PCIe connectors

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    FDB fan

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    Semi-passive mode

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    Ability to switch to multi +12V rail mode

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    10-year warranty


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    OCP at 5VSB

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    Bulky ATX, EPS and PCIe cables

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    A little higher conducted EMI compared to the HX1000 and HX1200

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    Short distance between peripheral connectors

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    Inrush current (230V)

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Features & Specifications

One of Corsair's newest PSU families is the revamped HX series, which includes four models with capacities ranging from 750W to 1200W. All of them feature fully modular cabling, 80 PLUS Platinum and ETA-B certifications, and quiet operation under the toughest conditions.

The biggest difference between the HX and pricier HXi models is the former's lack of a digital interface, meaning they don't get the benefit of partial fan control and monitoring through the Corsair Link software. But the HX PSUs do come with Corsair's Type 4 cables, featuring extra filtering caps and more sense wires on the 24-pin ATX connector. As a result, we expect better ripple suppression and tighter load regulation compared to the supposedly higher-performance HXi models. We do believe that Corsair will soon start bundling the Type 4 cables with its HXi series as well, though, to close this strange performance gap.

Interestingly, the HXes aren't much cheaper than the HXis, particularly when you look at the lower-capacity versions. When this review was written, the HX850i sold for just $10 more than the HX850, making it a no-brainer for enthusiasts wishing to adjust the power supply's fan profile and monitor its efficiency. 

We already reviewed the HX1200 and HX1000, so we have a pretty good idea how the HX family performs. Today we're turning our attention to the next-in-line HX850. It's powerful enough to accommodate a high-end PC with more than two graphics cards and a potent CPU. Because the HX850 has a couple of EPS connectors, it won't face any compatibility problems with motherboards needing more than one EPS socket, either. In our opinion, all 850W PSUs should be set up this way. But it seems like not all of Corsair's competition agrees.


Besides its 80 PLUS Platinum rating, this PSU also carries the ETA-B and LAMBDA-A+ efficiency and noise certifications from Cybenetics. Its top operating temperature for 100% output is set at 50°C, as the ATX spec dictates. In addition, the PSU is covered by all necessary protection features, including OTP and OCP on the +12V rails (when multiple +12V rails are enabled through a switch located on the back).

The cooling fan is the same one found on all of Corsair's high-end power supplies. It uses a fluid dynamic bearing and has a low maximum speed, so even in worst-case scenarios it doesn't make much noise.

Finally, a 10-year warranty is one of the longest covering a power supply. Only Seasonic offers something longer: its Prime models feature 12-year coverage.

Power Specifications

Swipe to scroll horizontally
Max. PowerAmps252570.830.8
Total Max. Power (W)850

Corsair serves up close to 71A on the +12V rail, 3A for the 5VSB rail, and 150W maximum combined power for the minor rails. The 5V and 3.3V rails of similar-capacity PSUs generally aren't as strong. But we've also noticed that, in most cases, their OCP triggering points are also set very high.

Cables And Connectors

Swipe to scroll horizontally
Modular Cables
DescriptionCable CountConnector Count (Total)Gauge
ATX connector 20+4 pin (600mm)1116-20AWG
4+4 pin EPS12V (650mm)2218AWG
6+2 pin PCIe (670mm+100mm) 3616-18AWG
SATA (450mm+115mm+115mm+115mm)2818AWG
SATA (450mm+110mm+110mm+110mm)2818AWG
Four-pin Molex (550mm+100mm+100mm)2618AWG
FDD Adapter (+100mm)1120AWG

There are two EPS and six PCIe connectors, along with 16 SATA and six peripheral ones. Corsair's cable length is satisfactory. However, we cannot say the same for the distance between SATA and peripheral connectors, which is too small.

Power Distribution

There is a switch that lets you choose between one +12V rail or multiple +12V rails. Across the HXi family, this is achieved using Corsair Link software. However, since the HX models don't have a digital interface, a different approach had to be used.

The +12V rails can deliver up to 40A each in multi-rail mode. According to Corsair, each individual connector has over-current protection, so no more than 40A goes through any given cable.

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Aris Mpitziopoulos
Contributing Editor

Aris Mpitziopoulos is a contributing editor at Tom's Hardware, covering PSUs.

  • ilogic450
  • derekullo
    Would it be possible to do a comparison between the Corsair HX850 and the AX860?

    All digital sounds nice on paper, but how does it translate into power supply performance?

    Does the extra $12 for the AX860 give you a quantifiable difference between them?

    And if the AX860 does turn out to be superior in some way then why does the HX850 even exist in the first place?

    Corsair AX860 $181.99

    Corsair HX850 $169.99

    I remember back in 2002 I blew my power supply while overclocking and playing Tron 2.0 .
    (The power supply didn't take out anything, just had to buy a new one.)

    Ever since then I've always used the highest priced AX line, with the rationale of never going cheap on my power supply again.
    (And being more conservative with my overclocks)
  • mauro2003_9
    The AX860 OEM is Seasonic.
  • Aris_Mp
    The AX860i has 1.42% higher overall performance score than the HX850 and the AX860 is very close to the AX860i. I would say that the performance of the AX860 and the HX850 is really close, however the second is much more silent.
  • Dark Lord of Tech
    Congrats to Corsair on another stellar PSU , and thanks for the review.
  • ElectrO_90
    The first paragraph talks about the HX850i and the new cables in this HX850.
    Where are the comparisons between the 2?
    Why even mention it, if you aren't going to show how much better the HX850 cables are, if at all?