Corsair RM850x ATX v3.1 PSU Review

Epilogue

The new Corsair RM850x, besides meeting the strict ATX v3.1 transient response requirements, which ask for operation at 200% transient loads for short periods without its rails dropping lower than the specified limits, also achieves a high overall performance rating thanks to its tight load regulation, good ripple suppression, the extended hold-up time, the highly efficient 5VSB rai, the dead low vampire power, and the high power factor readings. Moreover, its build quality is high, and the fan that Corsair used is also of high quality so that it won’t bother you in the long run. The fan speed adjustment knob will come in handy if you want to set the lowest fan speed manually. This means that the new RMx units are compatible in any case you decide to install them since they can be installed with the fan grille faced downwards or on the side, something that would be a problem for units that have semi-passive fan operation, which cannot be adjusted or switched off.

Let me further explain that. Say you have a semi-passive PSU where this feature cannot be switched off, and you want to install it in a chassis with its fan facing downwards. When the PSU’s fan is not operating, the hot air will be trapped inside the PSU so that the semi-passive operation won’t last long, and on top of that, it will frequently start the fan. FDB fans take the most stress during the start-up phase, where the lubricant has to go up to the shaft to minimize the friction. This is why I don’t suggest semi-passive PSUs where this feature cannot be deactivated in chassis where the PSU has to be installed with its fan facing downwards or on the side. Or in chassis where the PSU compartment doesn’t have airflow vents at its top side.

Semi-Passive Fan mode On – The hot air will be trapped inside the PSU!	The hot air goes up, so it won’t be trapped inside the PSU when the fan is stopped.

Back to the RM850x, the 12V OCP and OPP are conservatively set, below 130%, but the triggering points at high temperatures should be notably lower than those at lower temperatures. The OCP triggering points on the minor rails, mostly at 3.3V, need some adjustments, too. Lastly, it is nice to see the fan failure protection implemented. Most of today’s high-end PSUs lack this feature, which is of immense importance. If the fan stops operating, the stress applied to the PSU will be high, and only if over-temperature protection is present and works well will you avoid drama. This is why I decided to add a bonus for fan failure protection to my performance algorithm (it will be implemented in the following days).

• Corsair RM1000x ATX v3.1 PSU Review

As I wrote in the RM1000x review, hopefully, the street prices of the new RMx units will be lower than the MSRP ones because the RMx line has gained so much popularity due to its high performance per price ratio. At $150, the RM850x is more expensive than the competition. Nonetheless, it uses a unique platform developed by Corsair’s and CWT’s engineers, and in the worst case, you will pay $30-50 more to get a PC part, which you will keep in your PC for many years to come. I am not trying to sugarcoat the $150 official price tag. However, I am tired of hearing that PSUs are expensive when so much work and time is required for their development, with some brands like Corsair taking the extra step and developing their platforms. At the same time, other PC parts like graphics cards have sky-rocketed prices, and still, people buy them. We should mainly complain about the increased GPU, CPU, and mainboard prices since these parts are way more expensive than PSUs, and we typically change them much sooner! Remember, a good PSU is an investment!

Before investing in a new power supply, read my Best ATX v3.x PSUs article to check all alternative PSU offerings. You help me a lot by using my affiliate links, which don’t increase the product’s price. I get a commission from Amazon every time you do it, which can make a difference for me, especially now that I am on my own, working exclusively for my media and not for someone else.