Corsair RM850 850-Watt 80 PLUS Gold Power Supply Review

Corsair introduces its first non-digital power supplies integrated with Corsair Link. Let's take a look and see how it performs.

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Manufacturer: Corsair
6 minutes & 7 seconds read time

Introduction, Specifications, Availability and Pricing

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Up to this point, the only power supplies that we have seen that come with the ability to be controlled and monitored by software have been digital power supplies. We even have another unit on our test bench that is new to the market with its own software, but it is still a full digital unit. The digital units have proven to be some of the best on the market, but they often come at a price. The new RM series from Corsair helps bridge the gap a little.

It does this by adding the Corsair Link capability without being a full digital power supply. This will make the unit more cost effective to the consumer, but it may also mean that it simply doesn't perform like an enthusiast grade digital power supply.

Today we have the RM850 on our test bench, but the power supply is available in six different wattages from 450W to 1000W. The RM series is fully modular and also compatible with Corsair's individually sleeved cables which you can check out here. Let's see what the RM850 is made of.

Specifications, Availability and Pricing

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The RM850 features a single 12V rail capable of 70.8A or 849.6W. Both the 3.3V and 5V rails are rated for 25A each with a combined maximum output of 150W. The 5VSB is rated for 3A or 15W. Maximum combined output for the Corsair RM850 is 850W.

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The RM series isn't intended to be a flagship power supply for Corsair, but it does do a good job of filling out our Feature Summary. All protections are preset, which is something that we've come to expect from any power supply that bears Corsair's name on it. The RM850 is fully modular and features flat ribbon cables entirely. The RM850 is rated for 80 PLUS Gold efficiency. Finally, the RM850 is not certified for 100% continuous output at 50C, but Corsair does state it is rated for so at 40C.

The RM850 from Corsair has an MSRP of $149.99. This makes the Corsair RM850 very comparatively priced with other units on the market that have been out for some time. At the time of writing, Newegg seems to be the only place that has it in stock at the time of writing this article and they are currently $10 over MSRP, coming in with a price tag of $159.99. Corsair offers a five year warranty on the unit.

Packaging

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The front of the packaging for the RM850 gives us quite a few highlights of the unit, such as it being low noise, fully modular and Corsair Link ready.

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On the back, we find that the fan doesn't engage till the power supply hits 40% load. This will keep the noise down most of the time, until something CPU and GPU heavy is started.

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The right half of the back is mostly for other languages, but it does give us the I/O specifications too.

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Corsair lists the connector availability on the top of the box.

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Flipping to the bottom, we find a little bit more out about the unit. Also note that there is a chart on the right that shows where the unit sits in relations to all of Corsair's offerings for power supplies.

Inside the Box

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Corsair always does a great job packing their power supplies. We've yet to receive one packed like this that was damaged in any way, even if the box had been abused during shipping.

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Corsair's RM850 features a semi-gloss black finish on the unit. The top of the power supply features the I/O specification label.

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Both sides of the RM850 feature the same logo with it being inverted on the other side.

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The front features all of the modular connectors including the one for the Corsair Link adapter.

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The back doesn't have anything special as it is just your typical honeycomb mesh with on/off rocker switch and AC input. There is also a sicker back here that warns you the fan will not spin at low load levels.

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The 135mm tan fan inside RM850 is covered by the black wire mesh grill on the bottom.

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All of the modular cables are fully sleeved.

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All cables are fully modular and all of them are of the flat ribbon type too.

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If you intend to use the Corsair Link software, you'll have to purchase the Analog Corsair Link adapter separately from the power supply. Corsair sent us one along with the power supply so we could check out how it integrates with Corsair Link. We'll have a separate review of this shortly.

Cabling Arrangement and A Look Inside

Cabling Arrangement

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The Cable Summary looks a little more complicated than it really is. Corsair does a good job of providing cables and connectors with the RM850. For those that need it, there are two EPS12V connectors included. PCI-E connectors come in three cables with two connectors each giving you the ability to power three GPU's. SATA cables come in long and short varieties to reduce cable clutter.

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Rail distribution is as simple as it gets with a single 12V rail. There is no need to worry about load balancing here.

A Look Inside

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Opening things up, we find the first power supply that we've ever seen designed by Chicony Power Technology. They are a Taiwanese based manufacturer. Curiously enough, Chicony only makes the 750W and 850W RM power supplies. We'll certainly want to take a look at the other wattages to see how they compare.

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A Nichicon bulk capacitor sits on the primary side of the power supply.

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The secondary side is littered with a bunch of Taicon caps. We've not seen Taicon capacitors before either, but even though they are Taiwanese made, they are also a division of Nichicon and are quality capacitors.

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Cooling our RM850 is Corsair's NR135L 135mm fan.

Test Results and Final Thoughts

Test Results

Our load tests utilize a couple of FAST ATE active load testers and a variety of other equipment such as an oscilloscope, power conditioner, temperature probe and a power consumption meter. You can read more about our standard testing approach here.

The tests performed are based around six conceivable setups that are out there and progressively load down the PSU up to the power supply's limits or 1000W, whichever comes first. Since our test equipment's limits are higher than that of the Corsair RM 850W power supply, we can test it to the maximum.

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The above tests represent typical loads that we have measured from various systems and are meant to give a rough idea of where your computer might fall in line with our tests. Please keep in mind that each system is different and actual loads can vary greatly even with similar hardware.

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Let's start by taking a look at the voltages to see how well this unit did during testing. Starting with the 12V rail, we see 2% regulation from start to finish with a total drop of .21V. The 5V rail managed to stay within 3% of specification with a total drop of .11V from start to finish. Moving towards the 3.3V rail, we see that regulation was within 3% of specification with a total voltage drop of .10V.

DC Output quality for the Corsair RM 850W was good and well within specifications. During Test 1, we saw 12mV of noise on our scope. When we increased the loads in Test 3, the ripple climbed to 25mV at a little over half load. During Test 5 under a load of 850W, the oscilloscope showed a maximum of 39mV on noise on the 12V rail.

The Corsair RM 850W is rated for 80 PLUS Gold efficiency. This means that the power supply must perform at 87%/90%/87% efficiency at 20%/50%/100% loads respectively. As you can see, the Corsair RM 850W passed on our bench, and wasn't close to failing at any point.

Final Thoughts

Corsair definitely has a solid hold on the power supply market right now. The AXi series is still almost impossible to beat all the way around and enthusiasts are gobbling them up like crazy. The opposite end of the market is filled by the CM series, which is also selling like hot cakes because it is a quality unit on the very cheap side of things. The RM series resides right in the middle of all of this and brings some of the enthusiast features down to where the average guy can afford them.

On top of this, the RM850 has some solid performance. Voltage regulation is within 3% across the board for all rails. DC output quality is relatively good as well, staying under 40mV at full load. Even the efficiency is spot on for 80 PLUS Gold just as it is rated.

This is all before you factor in the ability to use Corsair Link to monitor your power supply. Throw in the price tag of $150 and you've got a combination of performance and features that that I think is going to be hard for anyone to overcome soon.

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Zac provides professional IT support by day, but plays the role of enthusiast by night. He's been building high-end custom computer for the nearly fifteen years and writing PC hardware reviews for the better part of a decade. Aside from computers, he also dabbles in quite a bit of home A/V equipment. Throughout the years, Zac has picked up an extensive knowledge of power circuitry and leverages this to provide the PSU reviews. When not found testing or writing, you can often find him speeding through the winding countryside on his motorcycle.

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