Corsair rm850 review in Spanish (full analysis)

We already have with us the new Corsair RM850 power supply. A new consignment of PSUs announced and presented at Computex 2019 that we had the opportunity to see work there and that its arrival was immediate. With three versions of 650, 750 and 850W, these sources with 80 Plus Gold certification, are completely modular and are ready to delight users who cannot afford the top ranges of the brand. In addition, it implements the Zero RPM Mode technology for the management of the 135 mm fan and a 10-year warranty.

As always, before starting we want to thank Corsair for giving us their product to carry out this analysis.

Corsair RM850 technical characteristics

Unboxing

We start by unboxing this Corsair RM850 power supply, the first in power after the 750W and 650W version that Corsair also has for sale.

The presentation has not changed one iota from the other versions of Corsair fonts. So we found a thick, rigid cardboard box with a size quite adjusted to the dimensions of the font, and showing off the colors that distinguish the brand, black and yellow of course.

On the main face of the box, we have a large photo of the font, as well as brand, model, 10-year warranty, and the 80 Plus certification it has. And if we turn the box to the other side, we will have information about the data sheet of the source, and very important information in the form of graphs of its efficiency at different loads, moment of activation of the fan and the power table. All this is very interesting and that we will discover little by little.

And without further delay, we begin by opening the box where we find two well-differentiated departments. On the one hand, the power supply embedded in two high-density polyethylene foam molds, and on the other hand, a second cardboard box where all the cables included in the bundle are located.

This is how we will have the following elements:

• Corsair RM850 power supply Modular connection cable pack (we will see them in detail later) 3-pin main power cable User manual Grips for installing cables in the chassis

Nothing out of the ordinary or anything to object to, everything very well ordered and within reach of the user. Later we will see all the cables that we have available.

Exterior design

Well, with everything out and completely scrambled to be used, let's look at the exterior design of the fountain and some elements of interest.

And in the first thing that we should look at Corsair RM850 is that the label and the performance table for the different voltages has been removed from the side areas. Some areas where we only see the model of the power supply, in this case "RM850" in large size.

It would have been an interesting detail to include the stickers that the Corsair AX series has for these sources, although we are not going to complain either. The design is quite elegant completely in black and the silkscreen in white.

As we have announced, in the part that we consider superior in most of the chassis according to the placement, we have the corresponding sticker with the power table on the different voltage rails. Let's note that, according to this, in the + 12V rail we have a maximum of 849.6W of power delivery.

Remember that this source of certification 80 Plus Gold, so it will offer a performance of between 88 and 92%. In fact, in the efficiency graph made by Cybenetics and that we will see later, efficiencies close to 94% have been obtained at a load between 100W and 300W.

We continue with the rear that faces the outside of the chassis. Corsair RM850 only offers a full metal honeycomb grille that serves to remove all the hot air that enters the fan from the bottom.

In addition to this, we have the typical three-prong connector for connection to our home network at 100 to 240V, with neutral, phase and ground, as it should be. In addition, we also have the typical switch that will be responsible for cutting the power supply to the source or allowing it.

Precisely in the part considered lower, we find a fan with a 135 mm diameter protected by a grille that will be responsible for introducing air into the electronic components.

Without further ado, let's look in detail at the Corsair RM850 cable management.

Connections and cable management

Corsair RM850 is clearly a completely modular power supply, which also offers a large number of connections on its rear panel. In this specific model we have the following:

Top row:

• 1x 24 + 4 pins (ATX) which is divided into two separate connectors 1x 6 + 2 pins / 4 + 4 pins (PCIe / CPU) 2x SATA / Molex

Bottom row:

• 4x 6 + 2pin / 4 + 4pin (PCIe / CPU) 3x SATA / Molex

Everything is quite clear in both rows, especially when we see all the cables that are included. As it is an 850W power supply, the manufacturer has provided it with enough capacity to install it in computers with motherboards of up to 2 EPS connectors for CPU. And even adding powerful GPUs, because as we'll see below, PCIe cables have dual connection on them, it's not the best, but it's a way to increase connectivity.

And why wait more? Let's see all the cables that the bundle of this Corsair RM850 source brings in its 2019 version:

• 1x 24 + 4-pin ATX cable for motherboard 3x 6 + 2-pin PCIe cables with double connection each, making a total of 6 2x EPS cables for 4 + 4-pin CPU with simple connection 1 x 4-pin cable (6-connector) with 4 MOLEX ports 3x 5-pin cables (6 connector) with a total of 12 SATA ports

This is the total cable count, if you have noticed, only one of the 6-pin SATA connectors would be free. What will we be able to with this 850W factory setting?

Well, let's see, we can install a computer with a double EPS connection motherboard for the CPU and we can also make an SLI with two GPU GTX or RTX, or also a CrossFire with triple GPU, hypothetically speaking. In any case, we would always have to look at the total sum of the powers of the different components to see if these 850W are sufficient. In any case, for a powerful motherboard and a top-of-the-range GPU, we're going to have plenty of power with this Corsair RM850.

As we have seen in the images, these cables do not have metallic mesh, so they are a different version than those included in the manufacturer's high-end sources, we are talking about the AX series or the RMX. Corsair makes available to users a page with the compatibility tables with the universal cables for replacement of the ones it makes.

We must also consider that these cables have the advantage of not having capacitors at their ends and of being flat, which facilitates the assembly because they are a little more flexible than those that incorporate them. Although a metallic mesh would have been very useful to improve aesthetics and increase their durability, precisely for this reason, we only have this mesh in the ATX connector and it also includes capacitors to improve voltage ripple.

Something that will also be interesting is knowing the total length of these cables, as the chassis are getting wider and sometimes, in certain custom configurations, users have trouble getting these cables to all components properly.

Format	ATX	EPS	PCIe	SATA	MOLEX
Length (mm)	615	665	750	810	780

We can make sure that you are not going to have any type of problems in the installation of components in the medium tower chassis and I include a complete tower. The large number of SATA cables that we have with up to 12 and the 3 PCIe, will ensure us excellent coverage throughout the chassis. Our only concern will be to make sure they are not seen.

Corsair RM850 internal review

Before starting the analysis, it is worth explaining superficially how to open this Corsair RM850 font. Basically we will place ourselves on the face where the fan is located and unscrew the four smaller allen head screws. Keep in mind that one of them has the warranty sticker, so inevitably if we do this we will lose it.

Next, we will remove the sheet metal and disconnect the fan from its two-pin connector to separate this element. This fan consists of a 135mm diameter configuration with 7 blades built by Hong Hua with Rifle type bearing. In this case, we do not have compatibility in Corsair Link, which allowed us to monitor the RPM of the fan.

But the most interesting thing is that this new update of the RM series sources have Zero RPM technology, which basically is about keeping the fan off while exceeding a power demand of at least 340W, and this has been demonstrated in our tests.

This new series of Corsair RM sources has been assembled by CWT and the truth is that they come with important updates regarding efficiency and current filtering to increase its quality. We have implemented a Champion-built CM6901 controller , necessary to meet Microsoft and Intel standards for low-load energy efficiency. And we don't have one, but two DC-DC converters, for the secondary + 5V and + 3.3V rails coming from the main + 12V.

In this Corsair RM850 source, we do not have management on multiple 12V rails, since this aspect has been left exclusively for maximum performance sources. So the power table is quite simplified, as we can see in the previous image. In fact, energy efficiency reaches 94% at 230V in a state of charge of between 20% and 50%, which is precisely the range where we are going to move most of the time, about 200W to 400W.

We start with the first stage of filtering where the presence of NTC accompanied by a relay (device that emits a “click” when we turn off and on) could not be absent, which will absorb the voltage peaks at the power input when we connect the cable or let's hit the switch. Next to these and on the main board, there is a MOV that is responsible for reducing surges that occur during the use of the source.

Likewise, we clearly see the two primary electrolytic capacitors made of aluminum by the Taiwanese Elite assembler that specify 3 90 µF both at 400V and withstanding temperatures of 105 ° C. Similarly, Elite has also been responsible for introducing the other secondary capacitors of this power supply.

In a general view you can see how the entire voltage rectification area and power stage is covered by a large aluminum heatsink. We must take into account that the diode bridge that converts the alternating voltage into direct, and the MOSFETS in charge of the power stage together with the transformers are the elements that can have the highest temperatures. There is also a secondary board with SR MOSFETs for the two rails of 3.3V and 5V that do not have this type of heatsink, and we will see later that they will be the ones that generate the highest temperature.

The protections that this Corsair RM850 source include overvoltages (OVP), undervoltages (UVP), power peaks (OPP), current peaks (OCP), over temperature control (OTP) and of course against short circuits (SCP).

Cybenetics performance tests

As the friend Breixo is doing in his last reviews of power supplies, we are going to draw up the charts corresponding to the data that Cybenetics has obtained on this Corsair RM850 source.

To better understand these tests, we will leave a complete explanation in the following tabs as it will be done in all sources that, like this one, include Cybenetics certification.

As the tests carried out by Cybenetics have some complexity, we explain in these tabs what is measured and what is its importance.

This is information that we will include in all our reviews with data from Cybenetics so, if you already know how the test structure works, you can continue reading. If not, we recommend you take a look at all the tabs to find out what each test is about.;)

• Glossary of terms Voltage regulation Ripple Efficiency Loudness Hold-up time

Let's go with a small glossary of some terms that could be somewhat confusing:

• Rail: PC sources that follow the ATX standard (like this one) do not have a single outlet, but several, which are distributed in " rails ". Each of those rails outputs a specific voltage, and can supply a specific maximum current. We show you the rails of this Thor in the image below. The most important is 12V.

  

  Crossload: When testing a power supply, the most common is that the loads made on each rail are proportional to their "weight" in the power distribution table of the source. However, it is known that the actual loads of the equipment are not like this, but are usually very unbalanced. Therefore, there are two tests called "crossload" in which a single group of rails is loaded.

  On the one hand, we have the CL1 that leaves the 12V rail unloaded and gives 100% at 5V and 3.3V. On the other, the CL2 that 100% loads the 12V rail leaving the rest unloaded. This type of testing, of limit situations, truly shows if the source has a good regulation of voltages or not.

The voltage regulation test consists of measuring the voltage of each source rail (12V, 5V, 3.3V, 5VSB) in the different load scenarios, in this case from 10 to 110% load.

The importance of this test lies in how stable all the voltages are maintained during the tests. Ideally, we like to see a maximum deviation of 2 or 3% for the 12V rail, and 5% for the rest of the rails.

What does not matter so much is 'what voltage is it based on', although it is a fairly widespread myth, it should not matter to us that the 11.8V or the 12.3V are around for example. What we do demand is that they be kept within the limits of the ATX standard that governs the correct operation rules of a PSU. The dashed red lines indicate where those limits are.

Vulgarly, it can be defined as the "residuals" of alternating current that remain after the transformation and rectification of the household AC into low-voltage DC.

These are variations of some millivolts (mV) that, if they are very high (being able to say that there is a "dirty" energy output) can affect the behavior of the equipment components and in some cases damage fundamental components.

A very guiding description of what a source's ripple would look like on an oscilloscope. In the graphs below what we show is the variation between peaks like the ones seen here, depending on the source load.

The ATX standard defines limits of up to 120mV on the 12V rail, and up to 50mV on the other rails we show. We (and the community of PSU specialists in general) consider that the 12V limit is quite high, so we give a "recommended limit" of just half, 60mV. In any case you will see how the majority of sources that we test give excellent values.

In the transformation and rectification processes from household alternating current to the low voltage direct current required by the components, there are various energy losses. The efficiency concept allows quantifying these losses by comparing the power consumed (INPUT) with that delivered to the components (OUTPUT). Dividing the second by the first, we obtain a percentage.

This is precisely what 80 Plus proves. Despite the conception that many people have, 80 Plus only measures the efficiency of the source and does not do any quality testing, protections, etc. Cybenetics tests efficiency and sound, although it altruistically includes the results of many other tests such as the ones we showed you in the review.

Another very serious misconception about efficiency is believing that this determines what percentage of your "promised" power the source can deliver. The truth is that the "real" power sources announce what they can give at the START. In other words, if a 650W source has 80% efficiency at this load level, it means that if the components demand 650W, it will consume 650 / 0.8 = 812.5W from the wall.

Last relevant aspect: the efficiency varies depending on whether we are connecting the source to a 230V electrical network (Europe and most of the world), or to 115V (mainly the US). In the latter case it is less. We publish Cybenetics data for 230V (if they have it), and since the overwhelming majority of sources are certified for 115V, it is normal for 230V to fail to meet the 80 Plus requirements advertised by each source.

For this test, Cybenetics tests the PSUs in an extremely sophisticated anechoic chamber with equipment worth tens of thousands of euros.

It is a room isolated from outside noise almost entirely, suffice it to say that it has a 300kg reinforced door to illustrate the great isolation it has.

Within it, an extremely accurate sound level meter capable of measuring below 6dbA (most have at least 30-40dBa, much more) determines the loudness of the power supply in different load scenarios. The speed the fan reaches in rpm is also measured.

This test basically measures how long the source is able to hold on once it is disconnected from the current while at full load. It will be a few crucial milliseconds to enable a safer shutdown.

The ATX standard defines 16 / 17ms (according to test) as a minimum, although in practice this will be more (we will not always be charging the PSU at 100% so it will be greater), and there are usually no problems with lower values.

And of course, we leave you with the complete test report published by Cybenetics:

Link to the full Cybenetics report for the RM850 Cybenetics official website

Voltage regulation

The calculated maximum deviations are perfectly in line with what is expected from a power supply like this. Although it is true that in the 12V rail we reached almost 1%, they are still practically negligible values.

Curly

As for the curl, it falls perfectly within the limits that have been established, although we do see that it is slightly greater when we subject the source to a greater load. Remember that we only have capacitors in the ATX connector, although it is true that the improvements that these capacitors will carry out will not be too important.

In any case, we are dealing with a non-Premium range source, and they are perfectly understandable values, and really good for what we have in our hands.

Efficiency

Seeing this graph we could almost be talking about a Titanium certified source, because we see records very close to 94% efficiency. Corsair stands out for being precisely a manufacturer that provides its sources with a lot of quality, and we only see records below 90% at minimum load and at a load that exceeds 100%.

Likewise, it is understandable that a source of 80 Plus Gold presents a somewhat higher consumption at the entrance, the more we demand of it, within the percentage of efficiency obtained.

Fan speed and loudness

Remember that this Corsair RM850 has Zero RPM mode, and therefore the fan activates when it reaches 340W of load from the source. This is precisely what we see in this graph, and the truth is that it is a fairly powerful fan capable of reaching 1753 rpm.

Reason for this is to find a noise close to 40 dB, let's understand, it is not too much, but it is audible in maximum stress situations, so Cybenetics gives it a LAMBDA A loudness certification , remaining a few steps behind the better records.

Hold-up time

Hold-up time Corsair RM850 (tested at 230V)	20.05 ms
Data extracted from Cybenetics

The Hold-Up time records are relatively close to what Intel sets, with those 16/17 ms of shutdown time. So we continue in the dynamics of having great results of this Corsair RM850.

We reiterate our appreciation to Cybenetics for allowing the use of this test data and invite you to learn more about it here.

Performance comparison

We have also conducted a small performance test with the Corsair RM850 source on our test bench.

TESTING BENCH
Processor:	Intel Core i9-9900K
Base plate:	MSI MEG Z390 ACE
Memory:	16 GB G.Skill Sniper X
Heatsink	Corsair H100i Platinum SE
SSD	Adata SU750
Graphic card	Asus ROG Strix GTX 1660 Ti
Power supply	Corsair RM850

For this, we have captured the demanded power without load, with Prime 95, and with prime 95 + Furmark with the Intel Core i9-9900K processor at a frequency of 5.0 GHz. These are the results:

And we see tremendously similar results between these two sources used on the same test bench and under the same conditions. Even the RM850 features slightly better registers than the Be Quiet! Which is very positive knowing that the latter have 80 Plus Platinum certification.

Thermal performance and loudness

We have also taken the opportunity to take a few thermal camera captures of this Corsair RM850 source during use at a load of approximately 360W to observe its heat distribution and the response of its fan.

Remember that this source has a microcontroller and a safety circuit that is projected on the small PCB where the fan is connected. In this way it is possible to control the semi-passive mode of the source much better with more parameters, we talk about the temperature, the load and the time of use. This also avoids the possibility of the fan entering on / off states when we are on the verge of those 340W of power.

After a few hours of use at the mentioned load, we have taken captures both with the source covered and its fan activated, as well as uncovered and without any refrigeration. In the first case we have obtained a temperature at the air outlet of about 36.5 degrees being at an ambient temperature of about 26 degrees. It is a fairly small load, we must say, so the source will have no major difficulties.

When we remove the cover, we see that the highest temperatures are recorded on the MOSFETS board located just behind the 3.3 and 5V rails. In this case we have taken captures under demand around 200W in the first photo, and with more than 340W in the second photo, observing temperatures close to 60 ° C. Similarly, under the aluminum heatsinks are also the rest of the power stages, although thanks to them the temperatures remain more controlled even without a forced fan.

Final words and conclusion about Corsair RM850

If the previous generation of Corsair RM fonts were good, this new generation, at least on this Corsair RM850 model, is simply wonderful. Above all, if we talk about energy efficiency, it is close to 94% efficiency with an 80 Plus Gold certification. Although of course, it will not hold up under all load situations.

The truth is that it is not one of the quietest sources we have tested. Its 135 mm fan and maximum 1700rpm will leave maximum values ​​of 40 dBA not negligible. At least the refrigeration will be great. A very interesting aspect is the implementation of a digital microcontroller for Zero RPM mode that intelligently manages the fan and keeps it turned off up to 340W of load.

We recommend reading our updated guide to the best power sources.

We did not forget the excellent internal components, such as the high-performance Elite capacitors, the CM6901 controller to increase efficiency, or the double DC-DC converter used for the 3.3V and 5V rails independently. These are quality details that different Corsair sources compared to the competition.

And finally we must talk about prices, because this Corsair RM850 source can be found in the market for a price of about 110 to 140 euros approximately depending on the models, namely RM650, RM750 and RM850. Without a doubt, they are really attractive prices for what we have in our hands, and nobody can have the excuse that their PC is not going to be able to put a good source.

ADVANTAGE	DISADVANTAGES
+ DESIGN 100% MODULES AND FLAT CABLES	- SAYING SOME, SOMETHING LOUD AT MAXIMUM LOAD
+ 80 PLUS GOLD UP TO 94%
+ GREAT SIGNAL QUALITY ON ALL RAILS
+ HIGH QUALITY INTERNAL COMPONENTS
+ 10 YEARS WARRANTY

The professional review team awards you the platinum medal and recommended product.

Corsair RM850

INTERNAL QUALITY - 94%

SOUNDNESS - 90%

WIRING MANAGEMENT - 94%

PROTECTION SYSTEMS - 95%

PRICE - 93%

93%

New RM series update comes with more and better