Corsair HX850 PSU Review

EMC Pre-Compliance Testing

EMC, EMI & EMS Acronyms

Electromagnetic Compatibility (EMC): The ability of a device to operate properly in its environment without disrupting the operation of other close-by devices.

Electromagnetic Interference (EMI): This represents the electromagnetic energy a device emits, which can cause problems in other close-by devices if it is too high.

Electromagnetic Immunity (EMS): Tolerance to electromagnetic emissions.

Equipment & Standards

To properly measure the EMI that a device emits, you need special equipment defined by the CISPR 16-1-1 specification. To learn more about our EMI testing equipment, please check out How We Test Power Supply Units.

In order to minimize EMI noise, some standards have been established. The corresponding standards for Information Technology products are CISPR 22 and its derivative EN 55022. In the EU, every product featuring the "CE" marking has to comply with EN 55022. Both CISPR 22 and EN 55022 divide devices into two classes, A and B. B-class equipment is for domestic environments, so its allowed EMI emissions are significantly lower than for A-class devices.

CISPR / EN55022 Limits
CISRP 22/ EN 55022 Class A Conducted EMI Limit
Frequency of Emission (MHz)Conducted Limit (dBuV)
Quasi-peakAverage
0.15 - 0.507966
0.50 - 30.07360
CISPR 22/ EN 55022 Class B Conducted EMI Limit
Frequency of Emission (MHz)Conducted Limit (dBuV)
Quasi-peakAverage
0.15 - 0.5066 - 5656 - 46
0.50 - 5.005646
5.00 - 30.006050

Conducted EMI Results

We use the EMCView software to conduct our EMC pre-compliance testing, which was kindly provided by TekBox Digital Solutions.

The HX850 exhibits slightly higher EMI than the rest of the HX-series PSUs we've reviewed. We believe that this is an isolated incident, though, given that the other models demonstrated EMI transmissions within the specified limits.

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6 comments
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  • ilogic450
    Thanks!
  • 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
    https://www.newegg.com/Product/Product.aspx?item=N82E16817139041

    Corsair HX850 $169.99
    https://www.newegg.com/Product/Product.aspx?Item=N82E16817139083


    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?