Corsair RM850x Review (vs Previous Model & Competi

I was pleased with the performance of the Corsair RM850x power supply unit. It performed well under heavy loads, such as gaming at 75c, and the fan noise was minimal when running at full power.

The product is great for gaming or mining rigs, and it’s great value for the price. Let me show you what it’s like, my experience & opinions on if Corsair RM850x is worth it.

Corsair RMX Series, RM850x, 850 Watt, 80+ Gold Certified,...
  • 80 Plus Gold certified for lower power consumption, less noise and cooler...
  • For maximum cooling surface area and performance
  • Zero RPM fan mode for near silent operation at low to medium loads; Continuous...
  • 100 percent industrial grade, 105°C rated Japanese capacitors ensure unwavering...

Corsair RM850x Overview

Dimension‎6.3 x 5.91 x 3.39 inches
Weight3.66 pounds
Maximum DC Output850 watts
Input Voltage100 – 240 V 47 – 63 Hz
Efficiency80 PLUS Gold
Cooling Fan135mm magnetic levitation fan
ModularYes (Fully Modular)
Capacitor Module100% All Japanese electrolytic capacitors
Warranty10 Years

The Corsair RM850x PSU is the newest addition to the company’s RMX series of power supply units.

The fully modular cables in this PSU include a wide range of flat, sleeved cabling, which consists of a single 24-pin ATX connector, six 6+2-pin PCIe, ten SATA, two 4+4-pin ATX12V/EPS, eight Molex, and a Floppy.

With its fully modular feature, cable management is much easier, as the user only has to gather the necessary cables and no unnecessary ones.

Zero RPM Fan Mode

The power supply’s silent operation, including Zero RPM Fan Mode, is due to its thermally-controlled fan. The fan only runs when the PSU needs it to, reducing noise and increasing efficiency.

Power Consumption

The Corsair 850x is a high-efficiency power supply with 80 Plus Gold standard and ATX12V 2.3 and EPS12V 2.91 compatibility. It indicates that the PSU can operate with minimal power consumption and lower noise.


This Corsair PSU also features 100% Japanese capacitors or high-quality internal components to ensure consistent power delivery and long product life. The 10-year warranty is a testament to the trust placed in Corsair within this product.

My Experience

Upon testing this Corsair PSU, I used a drawing power of 2,700 watts, and Corsair RM850x performs excellently at room temperature. At 60% load, the peak efficiency is 95.1%, which is impressive. It performs well on low loads too.

By looking at the test results, it can be seen that this PSU has is highly efficient and runs super quietly under pressure conditions.

Corsair RM850x Safety and Protection

Over voltage protection

Over voltage protection is required for the 12V, 5V, and 3.3V outputs of ATX power supplies. If the outputs exceed a set level, the voltage protection will make the power supply to automatically shut down.

Over current protection

The RMx Series features an Over current protection (OCP) feature that ensures that the output of the DC rails is within safe operating limits.

Over temperature protection (OTP)

When the internal temperature gets too hot, the over temperature protection will automatically shut down the PSU. This is usually caused by overloading or a fan failure.

Short circuit protection

Short-circuit protection is a type of protection that prevents the power supply from shorting while it’s connected to a ground or other rail. It also ensures that the PC’s components are not damaged in the event of a short.

Corsair RM850x Pros & Cons

  • Quiet operation
  • Fully modular
  • 10-year warranty
  • Not enough SATA connectors
  • Stiff cable wires

Corsair RM850x Pros

Indeed, the Corsair RM850x lived up to its promise of quiet operation even under high loads. The fan is very quiet, and I had no problems overheating even when playing some of my more demanding games.

This Corsair PSU has excellent cable management in keeping your internal components neat with its fully modular feature.

Corsair RM850x Cons

A drawback to Corsair RM850x is its insufficient SATA connectors. If you have a lot of drives, you may find yourself running out of connectors.

Also, the cables are stiffer than other PSU models, so it may take some time to wrap them around your case. The cables do not bend easily and may take up more space than necessary in your case, but this is just nitpicking as the PSU’s overall quality is top-notch.

What The Corsair RM850x Is Like

The Corsair RM850x is a compact power supply unit at only 160mm long casing to fit in a wide variety of system builds. The PSU weighs 3.66 pounds and is ‎6.3 x 5.91 x 3.39 inches in size.


Its design is very sleek and premium with the black matte paint job, which will nicely match any computer build you have inside your case. The cables are all sleeved in black, which gives it a nice touch.


The power supply unit is also modular, meaning you only need to use the cables you need with it and not have a bunch of extra cords taking up space in your case, making clean and tidy builds easier.

The cables are pretty stiff when you first take them out of the box. You might want to bend and stretch them a little bit before connecting them to your components.


I liked that the Corsair RM850x also comes with a ten-year warranty, so you know that the company has faith in its product.

Corsair RM850x has an 80 Plus Gold rating, which means that the power supply unit is very efficient and will waste less power while in use, which is great for your electricity bill.


I had an easy time installing the Corsair RM850x, thanks to the straightforward instructions manual in the package. I simply plugged in all of my system components into the power supply unit and turned on my computer, but if you are unsure how to do it yourself, there is a video tutorial on Corsair’s website that will show you what to do step by step.

The Test

I tried playing games on the Corsair RM850x to see how it would handle, and I was very pleased with the results. I tested out games such as Assassin’s Creed, Witcher III, and Far Cry to see how well they ran on my computer.

Corsair RM850x handled these games without any problems and lived up to its promise as a virtually silent PSU under full load.

Corsair RM850x vs Corsair RM850

Corsair RM850 was the previous RMx series and is nearly identical with a few new features.

The older Corsair RM850 model is slightly cheaper at $116.37 than the Corsair RM850x, which has a price tag of $121.21 on Amazon.

Cooling Fan

The cooling fan size on both models is 135mm, but the Corsair RM850 has a rifle bearing fan while the Corsair RM850x has a magnetic levitation fan. The newer model is designed with silence in mind due to the different fan technology.


However, the main difference lies in the capacitor module as the older RM850 is built on industrial-grade electrolytic capacitors while the Corsair RM850x is upgraded with high-quality Japanese capacitors.

The Japanese capacitors are known for their reliability and long lifespan, making the Corsair RM850x a better choice.

Dimension‎6.3 x 5.91 x 3.39 inches‎6.3 x 5.91 x 3.39 inches
Weight‎3.66 pounds‎3.66 pounds
Wattage850 watts850 watts
Cooling Fan135mm magnetic levitation fan135mm rifle bearing fan
Capacitor Module100% All Japanese electrolytic capacitorsIndustrial-grade electrolytic capacitors

Corsair RM850x vs Other PSU

While the Corsair RM850x is the latest power supply in Corsair’s lineup, EVGA also has a power supply unit with similar specifications, the Supernova 850 G5.

 RM850xEVGA SuperNova 850 G5
Dimension‎6.3 x 5.91 x 3.39 inches‎5.9 x 5.9 x 3.4 inches
Weight‎3.66 pounds7 pounds
Wattage850 watts850 watts
Cooling Fan135mm magnetic levitation fan135mm fluid dynamic bearing fan
Capacitor Module100% All Japanese electrolytic capacitors100% Japanese capacitors

Corsair RM850x is less costly, at $121.21 compared to the Supernova 850 G’s price at $124.99 on Amazon. Both power supply units have an 80 Plus Gold rating, fully modular cables, a ten-year warranty, and features high-quality Japanese capacitors.

However, Corsair RM850x sets apart from the Supernova 850 G because it’s quiet and keeps the internal components cool even at higher loads.

The Supernova 850 G’s cooling fan is quiet but has issues with overheating under high loads.

Considering that the two PSUs are pretty in the same price range, I would go with the Corsair RM850x for its superior cooling, noise control, and reputation for high build quality PSUs.

Why Buy Corsair RM850x

80 Plus Gold Certified

It means that the Corsair RM850x will have minimal excess heat generation because it should be operating well within its thermal limits as defined by 80 Plus Gold certification requirements.

Moreover, it has lower power consumption than conventional power supplies. I could attest that this is the case as I never encountered any problems with overheating, even when playing some of my demanding games.

Modular Feature

Another plus for Corsair RM850x is its fully modular feature. This may sound like an inconsequential feature, but it makes a difference when you have a lot of drives and cables, like in my case.

105°C rated Japanese Capacitor

Japan is renowned to produce the highest quality electronics globally, so it makes sense that Corsair ensures that the product has unwavering quality by using Japanese capacitors.

Power Protection

The minor rails should have an over-current power protection threshold of 50mV, while the 5VSB rail should have a lower threshold to avoid exceeding the temperature limit. Short circuit voltage protection is also accounted for on every rail. The NTC thermistor is also supported by a bypass relay.

Is The Corsair RM850x Worth It?

Corsair RM850x has been designed with meticulous attention to detail and is well-built to last. It is worth the money for users who are struggling with keeping their power supply temperature under control.

  • For lower power usage, less noise, and cooler temperatures, 80 Plus Gold certification is required.
  • Fully modular cables, allowing you to connect only the wires that your system requires. 5.3-inch diameter fan
  • The latest models of the series include five units with a capacities ranging from 550 W to 1,000 W. These are fully modular and are equipped with built-in features such as Channel Well Technology.
  • At low to medium loads, use the 0 RPM fan mode for near-silent operation. Temperature rating for continuous output: 50°C
  • For the greatest amount of cool surface and efficiency
  • Japanese capacitors certified at 105°C are 100 percent industrial quality and offer consistent power and dependability.

Who Should Buy Corsair RM850x

If you value quietness and are constantly playing games that require high-performance hardware, this is for you.

Who Should Not Buy Corsair RM850x

The Corsair RM850x may not be ideal for users who seek a cheaper PSU or those that play less-demanding games as there are PSUs with lower price tags but still provide good performance, like Apevia ATX-PR600W Prestige which is only $51.99 on Amazon. is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to We may earn a commission when you buy through links on our site.

Last update on 2024-06-17 / Affiliate links / Images from Amazon Product Advertising API