RM850 vs RM850X

Corsair RM850 VS. RM850X: Which Is Better?

Techies understand the importance of the PSU in their computers, especially if you’re building a gaming PC. The Corsair brand makes some of the best PSUs, but they come at different prices and specifications. So Corsair RM850 or RM850X, which should you choose?

In this article, I will highlight the features of these popular Corsair PSUs to help you choose the best one for your project. For a quick overview, let’s look at the differences they have:

  • Corsair RM850X has a longer hold-up time with less noise.
  • The RM850 has most of the RM850X features but is more affordable.
Key Specs Corsair RM850

Corsair RM850X

Capacitor module Made with industry-grade capacitors Made with 100% Japanese capacitors
Cooling Rifle-bearing fan design Uses a magnetic levitation fan design
Weight 1.7kg 1.71kg
Connector support 2 EPS connectors 3 EPS connectors
Size 162mm 160mm
Noise level test A- Standard++
Material Plastic Plastic
Warranty 10 years 10 years
Efficiency 90% at 50% load 92% at 50% load
Total Power 850 Watts 850 Watts
Fan model Hong His fan with 0.36 Ampere power Corsair fan with 0.27 Ampere power
Cooling Fan size 140mm rifle-bearing fan 135 mm Levitation fan
PSU type Fully modular Fully modular
Cost Less Expensive More Expensive

What Is Corsair RM850?

What Is Corsair RM850

Corsair RM850 power supply is a fully modular unit, meaning you can use only the cables you need. And they support high-performance processors and graphics cards.

Regarding efficiency, Corsair RM850 has 80 PLUS Gold certification, which means that it offers up to 90% efficiency at 50% load and up to 87% efficiency at 100% load.

Corsair’s RM850 is an ideal choice for high-performance PCs. It offers excellent voltage regulation and ripple suppression, and it has a fully modular design with a quiet 135mm fan.

Despite its high price tag, the RM850 is an excellent value because it can deliver its full power continuously without breaking a sweat. It’s a good choice for a gaming PC, but its capacitors are not top quality which may cause voltage drops in the PSU.

What Is Corsair RM850X

The RM850X is an 80 Plus Gold certified ATX PSU with a 100% Japanese capacitor design and is fully modular.

It should be able to deliver at least 90 percent power under 50 percent load.

This model also comes with a semi-passive fan design that allows it to operate without noise until it reaches about 50% load.

The fan will spin up slower than usual so that it won’t be as loud or distracting. If you’re looking for a top-tier PSU that will last you a long time and perform great, the RM850X should be on your radar.

The downside is that it has an in-cable cap design, so getting replacement cables is expensive.

Corsair RM850X Or RM850: Which One Should You Choose?

The Corsair RM series is a top-tier power supply line from the company. Their RM850 and RM850X are two of the best 850W power supplies on the market today.

They have similar designs and aesthetics, but the differences in their performance and features make them unique from each other. I will compare the two PSUs and which you should choose.

What I Like About Corsair RM850

  • High efficiency.
  • Microsoft Modern Standby compatible.
  • Fully modular.
  • 10-year warranty.
  • Good ripple suppression.
  • Zero RPM fan mode.
  • Multiple GPU ready.
  • 850 Watts continuous power.
  • 50°C output rated temperature.
  • 140mm rifle bearing fan for cooling.
  • Easy to install.
  • It is one of the cheapest in the RM series.
  • Compact design weighing 1.7 kg.

What I Like About Corsair RM850X

  • 100% Japanese electrolytic capacitors.
  • Zero noise with Magnetic 135 mm Levitation fan.
  • Easy to install.
  • Fully modular.
  • 10-year warranty.
  • High efficiency at light loads.
  • Zero RPM fan mode.
  • 850W continuous power.
  • Microsoft Modern Standby compatible.
  • Minimal inrush currents.
  • Multiple connector support.
  • Good ripple suppression.

Similarities Between Corsair RM850 And RM850X

The Corsair RM850 and RM850X are two power supplies with similar capacities and features. However, you should know some differences between these two models before deciding which to buy.


Both RMx and RM comply with safety requirements such as OVP (Over Voltage Protection), UVP (Under Voltage Protection), OTP (Over Temperature Protection), and SCP.

Under-voltage protection will kick in when rails drop below their minimum operating level for more than a few seconds.

Safety is essential for systems with multiple graphics cards that require an extra power supply connector for each card’s auxiliary power connector.

OTP protects against overheating by closely monitoring temperatures inside each rail using an internal thermistor probe attached directly to a heat sink. All of the Corsair RM power supplies come with a 10-year warranty.


The RMX and RM850 are 80 PLUS Gold certified. They deliver 850 Watts of continuous power and up to 90% efficiency at 50% load.

The modular design makes the PSU more efficient and quieter since fewer cables are inside the unit.

100% Japanese capacitors in RM850X with a 105° rating provides uncompromised performance and reliability. RM850, on the other hand, uses industry-grade Chinese capacitors of lower quality.

If you’re not into overclocking or extreme performance, you might be better off with the RM850.

Connector Support

They’re both fully modular in design, giving you the freedom to attach whatever cable connector your current PC build requires.

The Corsair RM850 comes with a single, 24-pin ATX connector, two 4+4 pin EPS connectors, and six 6+2 pin PCIe connectors. It can power your motherboard and up to six video cards.

In addition, it supports one 6-pin PCIe connector, three SATA connectors, and one Molex cable with four connectors.

RM850X is designed for multiple connector support. It supports a 12-pin GPU. It has three 2.92 version EPS 12V connections, three PCIe connectors, and fourteen SATA connector cables.

Corsair RM850 connector

Noise Levels

The cooler fan design for the Corsair RM850X series is unique. The RMX850 has a magnetic levitation cooling fan design, which is exceptionally prospective for high-temperature performance, unlike the RM850 series.

Compared to other series, the RMX series’ magnetic levitation cooling fan offers you a top-performing fan with exceptionally low fan noise.

It features specially engineered fan rotors that function with little bearing noise.

Additionally, the zero RPM mode design is beneficial while working with low to minimal load since it shifts to complete silence and activates when performance needs a check.


At $144.99, the RMX850 is more expensive than the RM850, which costs $139, but it’s worth it. Gaming enthusiasts would not mind getting more for a higher price. The RM850 has most of the RMX features, but it’s budget-friendly.


Both RM850 and RMX850 have sleek, compact designs, but the dimensions differ. RM850 is 152x87x162mm weighing 1.7kg while the RMX850 is 150x85x160mm weighing 1.71kg.

Related Questions And Answers

Is An 850w Power Supply Enough For PSU?

850 Watt power supply is enough even for a gaming PC. The Corsair RMX series offers a suitable power supply and efficiency.

However, if you’re building a high-end gaming PC or using multiple graphics cards in your system, you’ll want to consider getting a higher-wattage PSU up to 1000 Watts.

Why Should I Choose Corsair RM850X Series?

One reason you should choose the Corsair RM850X is its efficiency and design. The PSU delivers 850 Watts of continuous power and is 80 PLUS Gold certified.

It is fully modular, with the necessary cables for each usage. It is designed for multiple connector support and is completely noiseless. Although it’s pricey, its features make up for the price.

Are All Corsair Modular Cables The Same?

Corsair cables are the same except for the pinout of the 24-pin ATX cables, which are different. You can customize the ATX connector for the best possible performance and durability.

When you buy a Corsair PSU, you get more than just power. You’re also getting the assurance that your cables are built to last.

What Is An EPS Connector?

An EPS connector, also known as an ATX connector, is a power supply input used on personal computers (PCs).

It is the most common type of connection found on modern PCs, and it provides two connectors for 4-pin and 8-pin motherboard sockets. The abbreviation EPS stands for Entry-Level Power Supply Specification.

Are Corsair Power Supplies Good?

Corsair power supplies are good; they have an excellent reputation for quality and reliability.

Their RMX series has high efficiency at light loads and good ripple suppression. Both RM850 and RMX850 are fully modular and have excellent cooling.

Can I mix and match modular cables from different Corsair PSUs?

No, you cannot mix and match modular cables from different Corsair PSUs. Each PSU model has specific cable sets that are designed to work only with that particular PSU model. Using cables from different PSUs may result in compatibility issues and can damage your components.

How do I know if my PSU is compatible with my motherboard?

To ensure compatibility between your PSU and motherboard, you need to check the motherboard’s power connector and the PSU’s power connectors. Most modern motherboards use a 24-pin ATX power connector, and some also have an additional 4-pin or 8-pin CPU power connector. The PSU should have the corresponding connectors for your motherboard.

What is the difference between a semi-modular and a fully modular PSU?

A semi-modular PSU has some fixed cables that are permanently attached to the PSU, while the other cables are modular and can be added or removed as needed. A fully modular PSU has all its cables detachable, including the fixed ones. This gives more flexibility and customization options to the user, but it also tends to be more expensive.

What is the difference between a single-rail and a multi-rail PSU?

A single rail PSU has a single 12V rail that provides power to all components in the system. A multi-rail PSU has multiple 12V rails that are independently regulated and can provide power to specific components. Multi-rail PSUs offer better protection against overloading and short-circuiting, but they also tend to be more expensive and complicated to install.

My Verdict

The power supply unit is the brain of your computer. It is responsible for supplying the correct voltage and current to each component in your system. Corsair makes some of the best PSUs in the market; an example is the RMX850 and RM850.

On the question of between Corsair RM850 and RM850X, which one is better? I must say, in terms of efficiency, you can trust the RMX850 to deliver. Plus, it has a multiple-connector design.

The RM850 is also very efficient but at a lower price. Your choice depends on your budget and what you hope to achieve with a PC.

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