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Corsair HX Series 850W Platinum Power Supply Review

Author: Lee Garbutt
Manufacturer: Corsair

Final Thoughts and Conclusions

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It’s always a pleasure to test a Corsair power supply as they rarely disappoint and typically come with a good assortment of cables and connectors to hook up our test equipment. The HX850 delivered excellent voltage regulation across the board and AC ripple and noise suppression was also excellent; particularly the +12V outputs. And the power supply easily exceeded the criteria for 80 Plus Platinum efficiency certification, even while operating on 120 VAC and at elevated temperatures.

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The HX Series power supplies are all fully modular. The build quality is very good and Japanese made capacitors rated at 105°C are used throughout. The cooling fan is also high-quality and uses a Fluid Dynamic Bearing (FDB) for long life and quiet operation. The power supply starts out silent as the fan doesn’t start spinning until you hit about 40% load thanks to Corsair’s ZeroRPM fanless mode. Once spinning, the fan stays relatively quiet over most of the remaining output range and only became really noticeable at full load. And last but not least, Corsair is backing the HX850 with a 10-year warranty.

It’s hard to find anything not to like about the HX850 but while the daisy-chained PCI-E connectors will most likely serve the majority of users very well, we would prefer to see at least a couple dedicated connectors on single cables.

And don’t forget, Corsair offers essentially the same four HX models in their HXi Series, which includes the Corsair Link digital interface for software based monitoring and control.

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The MSRP for the Corsair HX and HXi Platinum Series power supplies are as follows:

Find these Corsair HX Power Supplies on!

•    HX750 $129.99 USD
•    HX850 $159.99 USD
•    HX1000 $199.99 USD
•    HX1200 $229.99 USD

•    HX750i $179.99 USD
•    HX850i $199.99 USD
•    HX1000i $239.99 USD
•    HX1200i $269.99 USD

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•    850W of Continuous DC output at up to 50°C
•    Excellent voltage regulation (±2%) on the three primary outputs
•    80 PLUS Platinum certified, with 90% efficiency at real world loads
•    Very clean DC outputs (low AC ripple and noise)
•    All capacitors are Japanese brand, 105°C rated
•    ZeroRPM mode for fan-less operation at low power (below 40% load)
•    Quiet 135mm cooling fan with Fluid Dynamic Bearing (FDB)
•    Switch allows selecting either Single or Multiple Rail +12V outputs
•    Fully modular cable set
•    Full suite of protection circuits: OVP, UVP, SCP, OPP and OTP
•    Active PFC with full range AC input (100-240 VAC)
•    10-Year warranty

Minor Weaknesses:
•    No dedicated PCI-E connectors on a single cable

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Corsair HX850 Platinum Power Supply

Our thanks to Corsair for sending us the HX850 PSU to review – thank you!

Video News

August 4, 2017 | 09:47 PM - Posted by Anonymousse (not verified)

PSU reviews are immensely boring.

August 5, 2017 | 04:54 PM - Posted by djotter

While the number of spectacular PSU failures has markedly decreased, reviews such as this excellent example are incredibly important when making purchasing decisions. Have a little respect for the work that Lee has put into this review.

August 6, 2017 | 01:19 AM - Posted by Anonymous... (not verified)

Maybe reviewers could spice up the format by testing PSUs to the point of failure. I would like to see what it takes to physically destroy these things. Can one take a 850W PSU to 1000W? What happens if I short an active power cable? What happens to thermals without the fan active? Can I add a waterblock to it in a custom cooling loop? There are so many interesting questions.

August 6, 2017 | 12:04 PM - Posted by Lee Garbutt

Virtually all enthusiast grade PSUs have built in safety circuits that are designed to protect the PSU from catastrophic failure. I have only had one PSU actually explode (fireball, sparks and smoke) during testing over the last fifteen years. Over Current protection or Over Power protection should shut the PSU down if too heavy a load is applied to a particular rail or the total output power is exceeded. Short circuit protection should shut it down if a short occurs on one of the outputs. And if the cooling fan fails, Over Temperature protection should shut the PSU down before it self destructs.  Boring but safe!

And water-cooling a PSU is possible (although maybe not practical). I have done this in the past by attaching several custom made water blocks to the PSU's existing aluminum heat sinks. I chose a PSU that was designed to operate fanless, removed the cover and attached three custom water blocks. Use your imagination... :) 

August 7, 2017 | 12:03 AM - Posted by EmeraldFlame (not verified)

Maybe I missed it but I read through the review and didn't see any info about what the 12v real switch actually does other then switching between single rail and multi rail mode.

Does this have any impact at all on the operation? Is effeciency affected? What kind of scenarios exist in which that feature is even useful? I can't really think of one, although I'm not a die-hard PSU junkie.

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