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Corsair RM850i Review

Corsair RM850i Review

It’s been a while since we last looked at a PSU, so lets change that today by taking a look at Corsair’s latest model which aims to offer a good balance between value, performance and features. This is our Corsair RM850i Review.

Corsair RM850i Review – Packaging and Bundle

corsair-rm850i-review-box corsair-rm850i-review-bundle

The Corsair RM850i arrives in a box which uses familiar styling for this brand, this time with a yellow twist. We get plenty of product info around the box and then inside we find the PSU protected by a foam block and protective bags. Both plastic and fabric. Also present is some product documentation, screws, ties and a bag of cables.


This is a fully modular PSU and the cables used by Corsair are flat with plastic coating mixed with braided. The standard connectors provided on the 850 watt versions of the RMi are:


Also worth noting for this PSU is the presence of a special cable which allows us to connect our PSU to our motherboard by USB. With that done we can then monitor our PSU using Corsair’s software. An alternate cable which is compatible with other Corsair parts is also supplied.

rmi-2 rmi-1

Shown above is Corsair’s Link software which you can download from here. Through this we can, amongst other things, monitor our system temperatures and aspects of the PSU (efficiency, output, temperature) as well as configuring the multi-rail mode of the unit.

Corsair RM850i Review – The PSU

corsair-rm850i-review-psu-1 corsair-rm850i-review-psu-2 corsair-rm850i-review-psu-3 corsair-rm850i-review-psu-4

As with their other units the Corsair RM850i uses a matt black finish and they go with a black and white colour scheme on the labels. Branding can be seen on the sides with an information sticker on the top. A grill covers the 13.5cm thermally controlled fan which is silent/off up to around 25% load. Turning the Corsair RM850i round we can see the modular connectors along with the ports for Corsair Link. Also present is a status LED and button. These are used to perform a quick test on the fan to confirm it is working correctly without the need to power on the system.

As far as the specifications go, this unit has a 12v spec of 70.8A with gold efficiency rating. The fan is a 13.5cm (fluid dynamic bearing) model and elsewhere in the unit we get all 105c Japanese capacitors (Nippon) and the unit is designed to give its full wattage at 50c. For protection technology we get the following on this range:

Over-voltage protection, under-voltage protection, short circuit protection, over power protection, and over temperature protection.

Corsair RM850i Review – Performance

At HardwareHeaven we use a custom built test bench, you can find more information on that here.

Corsair HX750i 40°C 210w 425w 635w 850w
3.3v 3.33v 3.32v 3.32v 3.31v
5v 5.01v 5.03v 5.01v 5.00v
12v 1 12.010v 12.001v 12.005v 12.010v
Efficiency 89.5% 90.1% 91.0% 89.1%
Noise Level (PSU Only) 0dBA 16dBA 20dBA 26dBA


Ambient Temp 25°C
Exhaust Temp 24°C 26°C 33°C 35°C


Oscilloscope AC Ripple (mV p-p) +3.3 +5 +12
850w 10 10 21


Corsair RM850i Review – Conclusion

As always with Corsair we get a unit which has a high level of build quality. The casing is strong, the finish applied to a high standard and the parts used all quality. The 105c Japanese capacitors for example are great to see in a value focused model and it was nice to see Corsair continue to include two bags to store our modular cables as well as retain support for Corsair Link. Corsair Link is a useful tool, in fact we like it more for their PSUs than Coolers, with all the key info on display in a nice simple screen.

Having the option to switch between a multi-rail and single rail design is a feature which allows the product to appeal to all consumers. Our preference (and the default setup) is single rail and in that mode the performance is very high. We get nice stable rails, the efficiency is spot on for the rating and temperatures are also reasonable. Ripple is very good for this class of PSU and fanless operation up to around 350w is great.

So that brings us to value where the Corsair RM850i offers many of the features and performance aspects of the higher priced models from Corsair, such as their AXi range but at a lower price point. When we add in the presence of a 7-year warranty and free software it is a very well rounded product indeed. For those looking at a choice between this and the HX equivalent, really the only change is in efficiency with a purchase price saving of around £40.

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About Author

Stuart Davidson

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