CM Real Power Pro 850W

Cooler Master’s latest entry into the PSU world is the most powerful and interesting unit we’ve tested to date. Will it perform at the highest level?

Category: Power Supplies
Manufacturer: Cooler Master
Product: Real Power Pro 850W
Gallery: Click Here
Price: $249.00

This year has been full of product releases touting certain features that one-up the competition. In the processor world we have seen the Core 2 Duo followed by the Core 2 Quad followed by the Quad FX. In the video card world we have seen the 7950GX2 followed by the X1950XTX followed by the 8800 series. This constant power struggle takes place across the board in the hardware scene year in and year out, just not necessarily as prominently as the aforementioned examples. One of the larger of these battles, and probably the most important of them all, is one that you may not have been paying attention to. This battle has been raging very strongly over the last year or so, and it gets more intense with each new release. It’s not a war between hard drives. It’s not a conflict between headphones. It’s not even a clash between motherboards. This battle is between what we have called the most important part of any computer: power supplies.

Power supplies today are constantly being marketed with various features emblazoned proudly on their boxes. “80% + Efficiency!”, “SLI Certified!”, “Silent Operation” and “Dual +12V Rails!” are the big ones you will find all over most power supply propaganda these days. It would seem on the surface that the manufacturers are just trying to inform their customers of the valuable features of the product. However, it is exceedingly rare that the claims made on power supply boxes have any sort of relevance to the consumer. All too often are people purchasing power supplies for what’s written on the box rather than what is inside. And we can’t blame them. Buying a power supply is one of the most difficult things to do when putting together a new computer. The only way to make an intelligent decision is to understand how a power supply works, what the numbers on it mean, and the reputability of the brand and manufacturer. This is not common knowledge by any stretch of the imagination. The perils of purchasing a power supply are enough to make even the most seasoned hardware enthusiast’s head spin.

When we saw the latest power supply from Cooler Master, we had one of those “…” moments. Cooler Master is not a company that is known for putting outrageous claims on their packaging, and they are certainly not in the business to deceive. So what could this “keystone” feature be that caused us to take a second look at this particular product? Well, the Cooler Master Real Power Pro 850W power supply sports “…the world’s first technology of six +12V rails.” Yes that’s right, six. 6 +12V rails. Let’s investigate, shall we?
{mospagebreak heading=Introduction&title=Specifications, +12V rails}

Specifications and +12V Rails
Before diving right in to this review, we think it would be appropriate to present some sort of background information on +12V rails, since that will undoubtedly be the main theme here. If you’ve read our comprehensive explanation of how a power supply works, you probably have a good understanding of what exactly rails are and why the +12V rail is important. If you haven’t, we strongly suggest you do that now, else much of what is about to be relayed might not make sense.

There are several steps electricity has to go through before it is ready to power your computer. Your power supply is responsible for getting it to that point, and those steps can be read about in detail in our previous article. One of the final steps, however, is very much relevant to this discussion. Inside the transformer, the current is tapped at various voltage levels, the very same voltage levels that are needed to run a computer. It is at this point, when the physical current is converted into various constituents, that power supply manufacturers begin to “mickey mouse” around. It’s the ugly side of the hardware world, and we hate to see it happen, but it happens nonetheless. Corners are cut, connections are made second rate, and the overall quality of the product is degraded – at the expense of the consumer. Perhaps the saddest part of it all is that there really isn’t much we can do about it. Aside from opening the power supply and taking a close look at it yourself, a task that most people have been persuaded against doing by shiny labels that warn about the risk of electrical shock, you kind of just have to buy the product and hope that it is what it says it is. Luckily, even if a product has been degraded in this manner, chances are that it is still a fine piece of equipment. In fact, there is nothing really dishonest with this practice at all. Without a definitive organization of power supply manufacturing standards, two companies can produce two power supplies with supposedly identical advertised specs that are, in reality, not so.

You see, there is more than one way to get the numbers that are supposed to represent power supply performance. Manufacturers use different methods to get certain features when those methods may not be the best way. The main feature that power supply manufacturers have differing approaches on is “dual +12V rails”. In the aforementioned article we explained how rails are generated from the transformers in the power supply. We gave a general description of how this is done without getting into the details. Well, without really getting any further into the details, there is no standard way by which rails are to be drawn from the transformer. That is to say that there is no limit on how many rails you can take off of one transformer (physical limitations yes, but none provided by a code of any sort), and there is nothing that dictates which rails you can take off of a transformer. Traditional power supplies, such as pretty much every single PSU produced in the last 5 years minus the last 6 months, draw one or two +12V rails and one +5V rail from the transformer. The +3.3V rail is then derived from the +5V rail in a secondary process to produce the three necessary rails for computer operation. However, the same number of rails can be drawn by using only two leads instead of the three in the above scenario. For instance, there could be 1 +12V tap on the transformer that is then split into two +12V rails, and one +5V tap on the transformer that then generates the +3.3V rail. Furthermore, some power supplies have their own dedicated +3.3V rail that is taken directly off of the transformer. The possible combinations, while not limitless, are certainly huge, and therein lies the problem. Everything we know to be true in the hardware world - everything that tells us that we know what we’re talking about - says that having a two dedicated rails on a power supply is more effective than having two rails that are derived from one. As far as we know there are no tests showing this exactly, but it is more in the principle than the result. If you claim to have dual +12V rails that are really just the same rail split in two, then you don’t really have dual +12V rails do you? Well, you kind of do… but at the core there is only one +12V rail taking the load of two +12V rails, right?

This is the big “dual +12V rails” conundrum we have been alluding to for about the last 4 paragraphs. Why does it exist? Why would a power supply manufacturer knowingly produce units utilizing this inferior design? There are two potential reasons we can think of, but only one that would seem probable. Firstly, perhaps the manufacturers do not know how to do tap two +12V rails. We consider this highly unlikely considering a company whose engineers do not know how to do this have no business producing power supplies. The more likely reason in our minds is that it is easier and more cost-effective to do so. In recent months we have seen the emergence of power supplies with not 2, but 3, 4, and even 5 +12V rails. While the genuineness of these rails are not something we can make judgment on without taking a good look at the power supplies themselves, it is abundantly clear that not all of these rails are “the real thing”.

So then, when Cooler Master sent us this Real Power Pro 850W power supply with 6 +12v rails to test, we had plenty reason to be skeptical. The only thing we could do was open it up and see for ourselves whether or not these rails were the real deal.
{mospagebreak title=Internal Features}

Internal Features
Moving away from our +12V rail theme for a while, let’s take a look at some of the other internal features of Cooler Master’s Real Power Pro 850W PSU. As is the case with most power supplies, the first thing you can see when you open up the RPP850 is the heatsink and cooling system. The particular heatsinks used in the RPP850 are basically the traditional right angle fins with smaller fins protruding in the opposite direction of most of the fins. Surface area is just as high as any other comparable supply, but the heatsinks lack the original design creativity we have seen on other supplies like the Silencer 750 from PC Power & Cooling. This is not a drawback by any stretch of the imagination, and the standard heatsink configuration used here is actually quite efficient in terms of space and cooling capacity. The active cooling in the RPP850 is provided by a 135mm fan that, suffice to say, is very quiet. Power supplies with a large, single fan cooling system tend to be far more quiet than their small fan or dual fan counterparts. The RPP850 is no exception to this rule, as the power supply cannot be heard above the hum of the Logisys 120mm LED fan mounted in the rear of the case. The 135mm fan is thermally controlled by the temperature sensor that is strapped to one of the heatsink fins (as seen in the picture).

Probably the second thing you will notice about the RPP850 is that it has two transformers. Modern power supplies, especially those touting a crazy-high maximum output and multiple +12V rails, are being made with two transformers. Some of these two transformer power supplies are, in reality, two smaller power supplies bolted together in one package. This was the case on many of the first power supplies that had maximum power outputs of 1kW or close to it. However, the RPP850 has two transformers integrated into the same PCB. This design has an increased efficiency over the previously mentioned one, because the current has less distance to travel, and will thus lose less heat. The fact that it has two transformers is also key, because this power supply claims to have 6 +12V rails, and output 850W of power. Having two transformers is an absolute must for such a PSU, since there is no way to draw 6 genuine +12V rails in addition to the various other rails from just one transformer.

The last thing to notice about the RPP850 is the mass of wires that are extruding from the side and out the back. This is the most important feature of the RPP850 for us, because it is where we will be able to tell whether or not the 6 +12V rails are indeed 6 +12V rails. What we are looking for are leads. The leads will be coming out of the power supply’s PCB in groups of two, each lead made up of one or two wires. As is the case in pretty much all power supplies, +12V lines in the RPP850 are represented by yellow wires. Therefore, each set of yellow wires coming out of the PCB is assumed to be a +12V lead. We would have to look really hard to find out what was what on the PCB, considering the bulk of wires is tremendous, but Cooler Master made it really say by labeling the PCB for each set of leads, or each rail. After a decent amount of finagling and eye strain, we were able to identify separate leads for all six +12V rails. What this means, quite simply, is that Cooler Master really has managed to squeeze six dedicated +12V rails into the Real Power Pro 850W power supply. We tried the best we could to take pictures of all the different rails, but it was pretty hard to do this thanks to the rigidity of the cables and the overhead heatsink. Nevertheless, here are the pictures.

{mospagebreak title=External Features}

External Features
The most striking thing about the RPP850 is the paint job. It has a fine mirror finish that reflects very well. This isn’t necessarily a very important feature of the power supply, but it will serve case mod enthusiasts well, considering it will readily reflect lights for a nice effect. Beyond the finish, you can clearly see the large 135mm fan mentioned above. Another curious feature of the RPP850 is the lack of a power switch on the back of the unit. We usually like to see a switch on the back of a power supply for safety reasons, as we are quite often messing around inside the computer while installing and uninstalling things. Certainly, having a power switch disengaged at least gives you the piece of mind that you won’t be electrocuted. On the RPP850, there is an LED that we assume represents whether or not it is safe to make changes to your computer. When the LED is green, the PSU is functional and delivering full power to the system. When the LED is orange, we assume that you can make some changes. However, removing the power cable inevitably is safer still, since it turns off the power completely, and really is not that much more difficult than flipping the switch. However, we could definitely see this being an issue for some people that value the ability to quickly switch their power supply on and off.

The final external feature of this power supply is the specification sticker. What is surprising about this sticker is that it is far simpler than what you would expect from a power supply with 6 +12V rails. Overall this label is no more complicated than the one we described in our "What’s a PSU?" article.
{mospagebreak title=Cables}

Cables
The Real Power Pro 850 has a TON of cables. Aside from the now-standard 20+4-pin motherboard connector, the RPP850 also includes an 8-pin +12V CPU connector for full EPS12V compliance. For users that do not have EPS12V compliant motherboards, the RPP850 also has a normal 4-pin +12V CPU connector. The RPP850 has 8 SATA connectors, a useful feature for those with massive storage arrays, as well as 6 standard 4-pin peripheral (MOLEX) connectors and 2 auxiliary power connectors (for floppy drives and older video cards). The real kicker on the RPP850 however, and the feature that is responsible for a lot of the marketing aspect of the product, is the inclusion of 4 6-pin PCI-E connectors. Up until one month ago, power supplies only really needed two of these connectors, because even the strongest SLI setup would only have 2 video cards, and thus, need 2 PCI-E connectors. However, with the launch of NVIDIA’s latest beast, the GeForce 8800GTX, 4 PCI-E connectors are needed, since each 8800GTX needs 2 PCI-E connectors.

Cooler Master has chosen to clearly label each major cable type to correspond to the appropriate sockets. While this feature is not really necessary for computer enthusiasts that could hook up power to a computer with their eyes closed, this feature can be tremendously useful to amateur computer builders who need all the help they can get.

Package
The Real Power Pro 850W shipped to us in a rather striking cardboard box that is aesthetical pleasing and very functional. It has a handle that makes for easy carrying from one spot to another. Inside the box, all of the components are packaged nicely in dense foam protection that keeps everything from moving around or being damaged during transportation. While this design is not the most fail-safe we have seen in our history of power supply reviews, it is certainly plenty effective at keeping everything secure.

Inside the package is just the power supply, the power cord, and a rather simple manual with installation information.
{mospagebreak title=Testbed and Methods}

Testbed and Methods
Test Setup

Case: Vigor Force
Power Supply: PCP&C Silencer 750 EPS12V | Cooler Master Real Power Pro 850
Motherboard: Intel Desktop Board D975XBX2 (Bad Axe 2)
Processor: Intel Core 2 Extreme QX6700 (Varying MHz)
Hard Drive: Western Digital 2500KS 7200RPM, 250GB with 16MB Cache Buffer
Video: ASUS GeForce 8800GTX | eVGA NVIDIA GeForce 7900GT KO Superclocked (580/1580)
Memory: 1024MB (2×512MB) Corsair XMS2 PC2 6400 (TWIN2X1024A-6400)
Optical Drive: Lite-ON SHW160P6S05
Cooling: Vigor Monsoon II
Audio: Creative X-Fi XtremeMusic
NIC: Killer Network Interface Card

Software Configuration

Motherboard BIOS: D975XBX2 Express BIOS Update (Rev. 2214)
Operating System: Windows XP Professional with Service Pack 2
Video Driver: NVIDIA ForceWare Version 96.89 (October 16 release)

This power supply is, by a pretty significant margin, the most powerful one we have tested to date. Therefore, our normal testbed would not really be adequate to stress this monster, so some modifications had to be made. In our Silencer 750 EPS12V review, we secretly used a Core 2 Extreme QX6700 processor to stress the unit. We will be using that processor again, as well as the Monsoon II TEC cooler from Vigor Gaming, as it uses far more power than any other cooling solution we have access to.

This time around we will also be using an 8800GTX, as it the most power hungry consumer level video card available today. For even more power consumption, we will toss in a GeForce 7900GT. The 7900GT won’t be functioning as a video device, but it will be plugged in and sucking up power. We will also be overclocking the processor in this system by well over 37%, to a total speed of 3.67 GHz, a full 1 GHz beyond stock for a QX6700. Due to stability problems, the RAM in the system will only be chugging along at increased voltage and not overclocked.

Detailed overclocked system settings consist of the following:

Processor Clock Speed: 3.67 GHz (roughly 37% overclock)
Processor Voltage: 1.5375 (1.35 stock)
MCH Voltage: 1.65 (1.5 stock)
RAM Voltage: 2.2 (1.9 stock)

{mospagebreak title=Tests}

Tests
We will be comparing the Real Power Pro 850W power supply from Cooler Master against the Silencer 750 EPS12V power supply from PC Power & Cooling. The outgoing supply previously tested with nearly perfect results, but on a system that did not consume as much power. Our first test will be at stock settings on the new system, let’s see how the 750 deals with the increase.

While these numbers are not as impressive as we saw in our initial tests of this power supply, the values are all still well with in spec, and certainly more impressive than 90% of the power supplies out there. However, the system under full load at stock settings consumes only 428 Watts. Granted, this is still more than it saw while overclocked in our previous test, but 428 will seem quite low when compared to the overclocked power consumption. Let’s take a look.

Here you can see that with the exception of the +12V rail, the 750 copes with the extra load very well. In fact, the performance on the +3.3V and +5V rails are just as impressive as we had seen in the past. However, the +12V rail suffers slightly from the increased load, probably because the 8800GTX is requiring far more power from the +12V rail alone than in the previous system. You can see that overall the performance of the 750 is quite impressive on this system. However, in order to power this system, we had to make use of a 2xMOLEX-to-1xPCI-E adapter. This was not too much of a problem for us, but it could be significantly frustrating for users with more peripherals that need power.

Cooler Master Real Power Pro 850W

Testing on this power supply was a little different than the ones we have tested in the past. We did the best we could to get readings on each +12V rail to get a better idea of the overall voltage stability, however it is difficult to trace each +12V lead from the PCB to the connector to isolate each rail. We managed to get readings on three different +12V rails by testing the yellow wires incorporated in the 20+4-pin connector, a standard MOLEX connector, and on one of the PCI-E connectors. First test was done at stock settings.

Here you can see that the numbers are not as impressive as on the Silencer 750 EPS12V power supply, but we have to stress that they are still well within spec. The difference of 4 to 5 hundredths of a volt that we see between the two power supplies really has no practical affect on system performance, it merely looks nicer to be closer to the target values. You can also see that there is a bit of difference between the voltages on each of the +12V rails that we tested. This affirms that the rails we tested were indeed three separate rails. It also shows that some of the +12V rails are going to be loaded more than others. Increasing the system clock speeds does not produce any surprises.

As you can see, all three rail types on the RPP850 suffered very slightly from the increased load. However, the performance of the power supply is essentially the same between stock and overclocked settings. Besides that, there really isn’t too much to say about these numbers.
{mospagebreak title=Final Thoughts and Conclusions}

Final Thoughts and Conclusions
Our main concern going into this review was having to test the validity of the +12V rails that are touted so openly with this power supply. It’s not every day a company pushes the envelope, and it certainly is not every day a company pushes the envelope in the power supply market. After doing some extensive testing, investigating, and evaluating, we can say that it appears Cooler Master has done just that. With 6 genuine +12V rails, 850 of power, and highly stable and accurate rails throughout, the Real Power Pro 850 should be a contender in the high-end power supply market.

Clearly our impressions of the Real Power Pro 850 and the numbers we have generated thus far in the review indicate that this is a very good power supply. Perhaps the only aspect of this product left to evaluate is its price. The RPP850 is sold across the net at the fairly reasonably price point of $250. This makes the RPP850 a full $50 more expensive than the very comparable Silencer 750 that was also tested in this review. However, the increased power output, just as impressive rail stability, and native ability to support dual 8800GTX graphics cards make this card a bit more attractive than the 750 in our opinion. The RPP850 is $30 less expensive than the TAGAN TG900-U95, which is widely considered to be the very best power supply on the market with a maximum power output of less than 1kW. We haven’t had any hands on testing with the TAGAN unit, we hope to very soon, so we cannot draw any conclusions between the two products. However, the RPP850 sports very similar features, boasts two more +12V rails, and various other features that are certainly comparable with the TG900-U95. The RPP850 is also the same price as the ToughPower 850W from ThermalTake. The ToughPower 850W has several advantages over the RPP850, most noticeably two of the 4 +12V ratings pushing 30Amps, as well as several disadvantages, including the lack of the 2 additional rails. We have not tested the ToughPower 850W yet either, but we have to assume it performs comparably to the RPP850. With this in mind it would seem that the Real Power Pro 850 from Cooler Master is an appropriately priced power supply that provides stable and reliable power to the hungriest gaming machines out there.

Pros
+ Six +12V rails
+ One large, very quiet fan
+ Sleeved cables
+ Mirror finish
+ High efficiency
+ Fairly stable and accurate voltage rails
+ Reasonably Priced
Cons
- Lack of an on/off switch
Rating
9.3 out of 10