Corsair RMx Series, RM850x Power Supply Review

Corsair RMx Series RM850x Power Supply Review

Even though a PC can be very power efficient and get by with modest power draws that don’t consume even 250W at their peak, there are cases when a PC needs much more power than that to function properly. High-end desktops that run advanced video and photo editing software or 3D rendering programs are one example.

The other are extreme gaming PCs with top of the line components such as the current most powerful graphics cards, often working in tandem through their manufacturer’s proprietary connection system.

Such huge power needs demand a lot from the power supply unit that is tasked to fulfill them. The Corsair RMx Series, RM850x Power Supply not only needs to be able to meet the high-power demands without a hitch, but there also needs to be many precautionary measures in place to protect the very expensive components in the system from suffering damage if ever the power supply fails. Corsair is one of the most well-known and respected power supply manufacturers in the world, and the RM850x is surely up to all the challenges mentioned above.

Features of Corsair RMx Series, RM850x Power Supply

PCs that are so power-hungry that an 850W PSU is needed to satisfy them also tend to get hot. A big selling point for the most prestigious processors and graphics cards is the ability to push them much more with overclocking, which in turn causes a lot more heat inside the case, even with measures like water cooling in place. One of the RM850x’s best features is the ability to offer peak performance even at temperatures as high as 50 degrees Celsius / 122 degrees Fahrenheit

At more reasonable ambient temps, the Corsair RMx Series, RM850x Power Supply either can’t be heard because its smart cooling fan won’t turn on if it is under a light load. Once it passes around 40%, the fan kicks in, but the noise levels remain practically the same as its huge diameter, of 135mm, and the rifled bearings, which keep it in place, help the fan be both effective and noiseless.

The RM850x’s modular build gives you ample room to manage all the cables. There is a total of 12 connectors, all evenly spaced out and clearly labeled. The box it arrives in contains a pouch which stores the varied selection of cables you can use. They’re flattened or sleeved, taking up less space than regular cables, having a lesser impact on the airflow within the case and contributing to cooler operation. They’re also all black, which is a nice touch from a design standpoint.

Voltage regulation, at or close to optimum, is essential at this level, and the RM850x performs admirably when tested for it. There is no more than a two percent fluctuation of the desired voltage, regardless of the load, which is quite impressive.

Even more impressive is the built-in ripple suppression that makes ripples all but non-existent at all three preset voltages. Although outstanding, these results aren’t that surprising because Corsair always uses the best-quality components when building its power supplies, including all-Japanese capacitors.


  • Certified as being 80 PLUS Gold, indicative of excellent power efficiency
  • Outstanding ripple suppression and above average voltage regulation ensure rock-solid power input at any given load
  • Noiseless operation at lower ambient temperatures as well as very quiet operation whatever the stress
  • High-quality internal components that contribute to the power supply’s overall excellent performance
  • 7-year limited warranty covering workmanship and factory defects


  • When the PSU’s fan isn’t spinning, it can create negative pressure in the PC case. This diminishes the other case fans’ capacity to pump hot air out of it, leading to higher temperatures, which cause more stress on the PC’s components
  • Every PCI-E cable has two connectors on its end. Having cables with a single one would be preferable


With the RM850x, Corsair proves yet again why the acclaim it enjoys is well-deserved. The RM850x is a testament to its engineering prowess. It is both a bit less expensive and has more features than its equivalent in the older RMI line.

The improvements made to it make the power supply more reliable and quiet while removing unnecessary things like Link support, so the end user is left with a more streamlined and appealing product to put into their high-end pc with absolutely no qualms.

If you have a serious PC-building project underway and require a power supply capable of keeping up with its insatiable appetite, then there’s really no reason to look any further than the Corsair RMx Series, RM850x Power Supply.

Installing it is a breeze, connecting only the cables you really need to it is a delight, and the performance it offers on a continuous basis should keep that PC running smoothly for years, and probably the next one you build after that too. Naturally, the price reflects its quality, but think of it as an investment into a system that will have no power issues whatsoever during its entire lifespan.

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