Corsair RM850i Power Supply Review

At Computex this year Corsair has announced a new variant of its RM series of power supply unit. Earlier we had the opportunity to review the Corsair RM1000i PSU and now we have the honour of reviewing the Corsair RM850i PSU. The new RMI series continues to offer 80PLUS Gold and fully-modular cable management in addition now features full Japanese capacitors, a 7 year warranty and a new electrical controller to lower the ripple, which were little higher in the original RM series.

Now let's see what this Corsair RM850i PSU has for us.


Premium components for great performance with very low noise
Corsair RMi series power supplies are 80 PLUS Gold certified and give you extremely tight voltage regulation, virtually silent operation, and a fully modular cable set. With all Japanese 105°C capacitors, they're a great choice for high performance PCs where reliability is essential. Corsair Link Digital makes it easy to monitor power supply performance, toggle single rail or multi rail mode, and control fan speed directly from your desktop.

Zero RPM Fan Mode
The superior energy efficiency of the RMi Series allows for the fan to remain off at low to medium loads for virtually silent operation. And when you're pushing it hard, the thermally controlled fan adjusts its speed to provide optimal cooling with minimal noise.

Configurable +12V rail
It's your choice – run it in the default multi-rail +12V mode, or toggle single-rail operation.

The power of Corsair Link Digital

Our advanced desktop application lets you monitor and log fan speed, voltages and power consumption, as well as control fan speed and configure +12V rail operation.

  • Corsair Link Integration for monitoring performance and adjustment of fan speed and multi-rail/single rail mode.
  • 80 PLUS® Gold efficiency, delivering 90% energy efficiency at real world load conditions.
  • ZeroRPM mode for fanless operation at low loads and outstanding noise reduction.
  • 135mm thermally controlled fluid dynamic bearing fan spins up as needed.
  • Fully modular cables for easy installation, less clutter, and helps maximize airflow through your computer's chassis.
  • Engineered to meet maximum power output at a server-grade 50°C temperature rating.
  • Fan self-test switch to determine fan functionality even before installation.
  • Over-voltage protection, under-voltage protection, short circuit protection, over power protection, and over temperature protection provide maximum safety to your critical system components.
  • Safety and Agency Approvals: FCC, ICES, CE, UL / CUL, CSA, C-Tick/RCM, TUV, CB, CU, KC Mark, RoHS, WEEE, RoHS (China), REACH



Corsair RM850i comes in a securely packaged yellow / while coloured box with PSU graphics, Model name and features highlights on front and the back of the box.

Inside the box

Outer box contains a cardboard box includes RM850i within velvet drawstring bag, Module cables within a pouch, Power cable, cable-ties , Corsair Link Digital interface cable, Corsair Link USB cable and User manual


Comparing with original RM Series Corsair has made little changes with RMi series. The stickers on the sides and the logo have been modernized, but the body shell remained largely the same.


Corsair RM850i power supply board is a CWT design and the build quality is actually very high and uses all Japanese capacitors in the primary and secondary stage.

Corsair are uses their NR135P fan (135 mm, 12 V, 0.22 A) inside the RMi Series 850W power supply. According to Corsair, the fan blades are properly balanced to help reduce resonance at higher speeds. This is a fluid dynamic bearing fan which helps in prolong life and reduce noise.


Test system configuration -

CPUIntel Core i5 6600K
RAM2 X 4GB G.SKILL Ripjaws4 DDR4 3000Mhz
SSDKingston SV300 120GB
CoolerCorsair H100i
GFX Nvidia Geforce 7950 x2
PSUCorsair RM850i
DisplayAcer S220HQL
OSWin 8.1 Pro / Windows 10

Custom made DC Active dummy load PSU tester.

Load Test

To test the PSU on my Active load test, I have manually increased the load in Amps on 12v first rail, 12v second rail, 5v and 3.3v rail to simulate 100%, 80% 50% and 20% load. Since this PSU is having only single 12v rail, so divided the load in half on both 12v loads on my tester.

5V stand-by and -12V supply was left at a constant 0.5amp load throughout the test run.

Maximum theoretical load handling capacity of my tester is somewhat around 1500W, but due to MOSFETs safe operating area (SOA) characteristics and thermal load handling capacity of the heatsinks, this tester can handle Max 1300W.. For safety reasons I have also installed a thermal controller which turn OFF the attached PSU if temperature exceeds SOA specifications.

During test the tester turned OFF the PSU after approx 12 sec at 100% load.


  • ALL Japanese capacitors
  • Fully Modular
  • Low noise fan
  • High build quality
  • 7 years warranty


  • Nil


Corsair RM850i PSU in our test showed good voltage stability and 80 PLUS Gold efficiency. PSU fan was idle at low and modest load, and was silent under full load too. The protection circuit OCP worked perfect and PSU turned itself off when tried to pull over 960 watts.

Finally Corsair New RM850i PSU is one of the best performance unit in the upper middle class of PSUs. With full- modular cables, all Japanese capacitors, Corsair Link and a 7 year warranty Corsair RM850i is best option for system builders looking for a high power and 80 PLUS Gold efficiency PSU is worthy of our PC TeK REVIEWS EXCELLENCE Award.

Manufacturers Info

Site Link