Cooler Master Silent Pro 700w Modular PSU Page: 1
Introduction & Specifications
Cooler Master LogoAs most of the silent PC enthusiast crowd will tell you, total silence is one of those things which can never quite be achieved. Even after going to extraordinary lengths to isolate Hard Disks, Fans and other devices from rattling your fully sound-proofed case, there is always one device that simply cannot be silenced in the same way as the rest - the PSU. Many manufacturers have already realized this and have designed their Power Supplies to be as kind on the ears as possible. However, PSU designs that incorporate features such as water cooling or passive cooling all have their downfalls, either transferring heat to another location where it needs to be cooled, or simply not packing quite enough punch to power the modern PC.
For this reason, most PSU manufacturers seem to have steered clear of these flawed cooling methods, instead concentrating their efforts on fan-based cooling with the lowest possible noise output. Cooler Master is one of these companies, and with an already good lineup of relatively silent PSU's coupled with beastly power outputs (such as the Real Power Pro M1000 and M1200), they now have their sights firmly set on reducing PSU noise even further in the recently announced Silent Pro series.
Silent Pro 700w Specs ListFeature List

1. Modularized cable design to eliminate clutter and improve airflow inside the chassis

2. Two 6+2 pin PCI-e connectors are compatible with future graphic card upgradeability

3. Eco-design for energy and money saving by 80Plus design (>85% efficiency)
4. Single +12V rail provides more power for over-clocking users
5. Compliance with Intel standard ATX 12V V2.3
6. Green power design to meet energy star and blue angel and RoHS requirements
4. Super silent operation with intelligent 135mm fan speed control
6. Multiple protections provide full-scale protections for your components (OVP/OCP/OPP/OTP/SCP)
7. High Power Density (150*150*86 mm)
8. High reliability (MTBF > 100,000 hrs)
9. Copper + Aluminum heat sink design
10. Flat cable design for better cable arrangement
11. Japanese Made Capacitor
12. Silicon rubber Pad
As the specifications above show, Cooler Master has tackled the problem of noise inside Silent Pro 700w unit we're reviewing today in four main ways: a 135mm fan with intelligent speed control, Silicone rubber gaskets to prevent vibrations transferring to the PC enclosure, effective removal of heat from the PSU mosfets (using a combination of copper and aluminium in the heatsink construction), and an overall high level of efficiency of 85%+. A lot of these methods have been used on PSU's in the past, but this is the first time any of us here at OC3D have seen all of these methods combined into a single unit.
Silent Pro 700w Rail Specs
Cooler Master have also taken us by surprise by opting for a single +12v rail capable of delivering an impressive 50 amps. This is a big step away from the recently reviewed Real Power M700 and Real Power Pro M1000 units that featured four and six +12v rails respectively, with each being rated between 18-19amps.
While Single- vs Multi-rail has always been hot topic for debate among PSU gurus, the single-rail configuration has always been a favourite for overclockers who prefer to have all their power readily available on a single rail. This avoids situations where one +12v rail is under heavy load from power-hungry devices such as an SLI/Crossfire graphics card setup, while the remaining rails are barely being utilized.

Cooler Master Silent Pro 700w Modular PSU Page: 2
One thing we always find ourselves commenting on when it comes to Cooler Master PSU's (and in fact most of their products) is their no-expense-spared approach to packaging. Even on their lower-end models, Cooler Master seem to go the extra mile, adding styrofoam padding along with elaborate bags and boxes to their entire range. Not only does this give the feeling that you've bought something extra special, but it also provides extremely good protection from rough courier companies.
Cooler Master Silent Pro 700w Box Cooler Master Silent Pro 700w Box Side
Cooler Master Silent Pro 700w Box Back Cooler Master Silent Pro Box Open
Nothing has changed this time round either, with the Silent Pro being packaged inside a plain black cardboard box with swing-open style doors. A half-width cardboard wrap-around also encapsulates the box, providing Cooler Master with somewhere to print the unit specifications and feature list, while also preventing the box doors from opening unintentionally.
Cooler Master Silent Pro 700w Box Open Cooler Master Silent Pro 700w Contents
A large chunk of styrofoam padding has been used to separate the PSU from the accessories bundle. This should prevent items such as the mains plug from scratching the paintwork on the PSU as they move around during shipping.  While on the subject of accessories, let's see what's included in the box:
- Mains cable.
- Bundle of modular cables.
- Cooler Master warranty card.
- Installation leaflet.
- User manual CD
- ATX screws (black)
Most interesting of all the accessories is the inclusion of a compact disk. At first, our imagination ran slightly wild with thoughts that we might actually need to install drivers for a power supply! But nope, all that's on the disk is a good old user manual in PDF format.
Measuring in at an extremely compact 150x150x83mm, the Silent Pro 700w has a very good size to power ratio and should easily be able to fit inside even the smallest of ATX cases without any issues. Unlike the Real Power Pro M700 and M1000, the Silent Pro doesn't come with any kind of fancy paint job or electroplating, instead opting for a fairly coarse and rugged powder-coated finish.
Cooler Master Silent Pro 700w Top Cooler Master Silent Pro 700w Bottom
As previously mentioned, a 135mm fan consumes the entire surface area at the bottom of the PSU, with a black fan grill preventing any stray cables inside your case finding their way into the fan blades. At the top of the casing, Cooler Master have livened up what is normally a fairly bland side of the PSU with a small embossed Cooler Master logo.
Cooler Master Silent Pro 700w Side Cooler Master Silent Pro 700w Side
The obligatory specification sticker is in its usual place at the side of the unit and mirrors the information found on the power output chart over on the previous page.  At the other side of the unit is yet another sticker, but this time only serves purpose to advertise what model of PSU you have installed inside your system.
Cooler Master Silent Pro 700w Front Cooler Master Silent Pro 700w Back
Comparing the Silent Pro 700w to the Real Power M700, we can see that Cooler Master have reduced the number of modular plugs from eight to six. This seems a bit strange considering both units are rated at 700w, and if anything the single +12v rail design of the Silent Pro will encourage people to plug more devices in.
Around the back of the unit is an extremely fine honeycomb mesh grill with a mains plug and power switch.
Cooler Master Silent Pro 700w Vibration Dampening Cooler Master Silent Pro 700w Dodgy
Finally, and probably most importantly, the Silent Pro features a silicone gasket around the front and back of the PSU to prevent vibrations from the fan transferring to the PC case. Initially we wondered why Cooler Master decided to place the gasket at both ends of the PSU, but in situations where the PSU sits at the bottom of the case, having silicone at both ends ensures that the entire PSU will be isolated from its surroundings.
Unfortunately the mounting of the gasket was quite poor, and as shown above, the glue used hadn't actually bonded with the PSU casing. This led to the gasket looking quite untidy and more of an afterthought rather than an integral element of the PSU.

Cooler Master Silent Pro 700w Modular PSU Page: 3
Internal Components
While the weight and size of a PSU can often give us a rough idea of how the unit is likely to perform, many manufacturers are now turning to newer and more efficient methods of manufacture, resulting in smaller and often lighter power supply units. However, by looking inside the Silent Pro we should be able to identify some of the components used and get a good feel for the overall build quality of the unit.
Cooler Master Silent Pro 700w Insides Cooler Master Silent Pro 700w Insides
The insides of the Silent Pro are fairly tidy, with only a few stray wires leading to the modular backplane that haven't been grouped together. All components inside the unit are fairly low profile, giving the airflow produced by the 135mm fan plenty of room to  dissipate, resulting in less "hot-spots". As previously mentioned, the heatsinks used to cool the mosfets inside the unit use a combination of aluminium and copper. This hybrid approach gives maximum cooling performance as copper is known for its excellent heat transfer properties and aluminium for its superior heat dissipation.
Cooler Master Silent Pro 700w Caps Cooler Master Silent Pro 700w Ferrite Coil
Cooler Master Silent Pro 700w Transformer Cooler Master Silent Pro 700w Transformer
Two low-profile capacitors have been used inside the unit, which should offer cleaner voltages in comparison to the Real Power M700, which only featured a single capacitor. As we can see from the image top-left, the capacitors are rated to run at up to 85°C, but unfortunately we couldn't find any manufacturer markings to determine their origins.
Also pictured above are the two transformers used within the unit. In normal PSU configurations, the larger of the two transformers is used to power the +12v rails, while the smaller is often used for +3.3v and +5.0v rails.
Cooler Master Silent Pro 700w Fan Cooler Master Silent Pro 700w Fan
The 135mm fan used inside the Silent Pro is manufactured by Yong Lin Tech and has a model number of DFS132512M. As we can see from the specifications below, the fan is able to push an impressive 82CFM through the PSU with a noise output of 37dB(A). Cooler Master undoubtedly chose such a powerful fan so that it could be run at lower speeds, thus producing an even better CFM-to-dB(A) ratio.
Make: Young Lin Tech
Model: DFS132512M
Rotation Speed: 2000RPM
Airflow: 82.41CFM
Noise: 37.98dB(A)
Cables & Connectors
The modular PSU has long been a subject for heated debate among PC enthusiasts. Many believe that adding extra plugs and connectors into the cabling system produces resistance, resulting in voltage drops and in some cases arcing. While others simply couldn't be without the greater tidiness and improved airflow that a modular PSU provides.
Cooler Master Silent Pro 700w Connectors Cooler Master Silent Pro 700w Fixed Cable
The Silent Pro attempts to satisfy everybody by hardwiring the cables that are essential to the operation of every PC (ATX & EPS-12v) into the unit, while leaving the non-essential cables (PCI-E, Molex) as modular. Not only does this make sense in terms of functionality, but it also ensures that the motherboard receives the cleanest possible power.
Cooler Master Silent Pro Cables Cooler Master Silent Pro Cables
Cooler Master have made a departure from the sleeved cabling used by almost all other PSU manufacturers in favour of a moulded plastic, ribbon-style cable. Not only are these slimmer than the standard sleeved cable (especially when bundled together with a cable tie), but they are also extremely flexible and look very cool.
Now all Cooler Master need to do is provide them in a range of different colours for the case modders among us!
Cooler Master Silent Pro ATX Cooler Master Silent Pro EPS-12v
Cooler Master Silent Pro PCI-E Cooler Master Silent Pro PCI-E
Despite the Silent Pro being a new unit to the market, Cooler Master haven't forgotten about those of us who don't have the very latest cutting-edge (power-hungry) components. Support for both 20-Pin and 24-Pin ATX motherboards is included, along with an 8-Pin EPS-12v connector which can be split in half to support older 4-Pin P4-12v motherboards. Both PCI-E connectors are also native 8-Pin, but can be reduced down to the 6-Pin standard in the very same way.

Cooler Master Silent Pro 700w Modular PSU Page: 4
Load Testing
To provide our readers with the most accurate results, Overclock3D uses a custom-built PSU load tester on all reviews. This not only gives much more reliable results than the testing methods employed by other sites, but also allows for all current and future review results to be compared side-by-side. The following table shows the load (in watts) that was applied to the Silent Pro 700w during testing.
Load Chart
Silent Pro 700w +3.3v
Compared to the results from the other rails seen below, the +3.3v rail seemed extremely solid and quite isolated from any load exerted on the +5v and +12v rails. This could possibly indicate that the smaller transformer pictured on the previous page is actually dedicated to the +3.3v rail, with the +12v and +5v rails sharing the larger transformer.
Silent Pro 700w +5.0v
Silent Pro 700w +12v
Under normal circumstances, we'd discuss the performance of the +5v and +12v separately, but as we can see from the graphs above, the results from the two rails are in some way directly related to each other...
With 0w load applied, the +12v rail is at a rather dangerous 12.95v, whereas the +5v rail is at the opposite end of the scale producing just 4.76v. Obviously no system is ever going to use 0w, so these results should not be taken into account when assessing the performance of the unit - but they are interesting never less.
Placing a 10 amp load across all three rails to produce a total load of 203w, the +12v rail comes down to a much more reasonable (but still slightly high) 12.48v. This seemed to have a see-saw effect on the +5v rail, with the voltage actually increasing to 4.90v. The same was also exhibited when placing a further 10a load on the +12v rail (Total load: 323w), with the +5v rail rising to 5.00v and the +12v rail falling to 12.35v.
Increasing the load to 20a on the +3.3v and +5v rails and 30a on the +12v rail saw the results swing back in the other direction.  This time the voltage on the +12v rail increased to 12.39v while the +5v dropped sligtly to 4.97v.
Applying additional load to the +12v rail in 10a increments up to a total of 50a (Total load: 766w) saw an expectable result of the +12v rail voltage dropping down to a minimum of 12.01v, but strangely, yet again the +5v rail increased up to 5.13v.
Efficiency Results
Efficiency tests are performed by measuring the wattage consumed by the power supply at the mains (Mains Draw) against the power consumed by the OC3D power supply stress tester (PSU Load). These results may not be 100% accurate, but have proven to be extremely close to results obtained from professional equipment.
Silent Pro 700w Efficiency
Throughout the testing, the Silent Pro managed an efficiency level of at least 81.9%. Depending on the load applied to each of the PSU rails, this efficiency level went as high as 85.7% at times, reinforcing Cooler Master's claims that the unit is able to achieve >85% efficiency.
Temperature, Fan Speed & Noise
As with all components in the modern computer system, the performance of a PSU can be directly affected by heat. Excess heat inside the PSU can easily have a negative effect of the maximum power output of the unit and lead to voltage instability. For this reason, Overclock3D includes temperature recordings taken from the PSU's exhaust using a thermal probe to highlight any potential issues that the PSU might have obtaining its rated output.
Silent Pro 700w Fan, Temp & Noise
Under normal circumstances, we'd also use a sound meter to record the dBA noise level output by the fan. However, the Silent Pro certainly lives up to its name and was so quiet that it was almost impossible to take an accurate dB(A) reading from the PSU without ambient noise affecting the results. Even with the fan voltage hitting 7.02v when at 766w load, the noise emitted by the fan was too low to measure and could only be distinguished from the din of a nearby motorway by placing my ear within 30cm of the cooling fan.

Cooler Master Silent Pro 700w Modular PSU Page: 5
Cooler Master Silent Pro 700wWith its single +12v rail, excellent modular cable system and a silicone gaskets to dampen vibrations, the Cooler Master Silent Pro 700w certainly looks like it has something for everyone, from overclockers to silent PC enthusiasts. However, as we've seen over on the previous page, the voltage stability of the unit is somewhat unusual, with both the +5v and +12v rails taking a roller-coaster ride depending on the distribution of load between them. While most of the time these voltages remained within ATX specifications and therefore shouldn't cause any issues, we can't help but wonder what kind of results a user would see with a configuration that exerts a very unbalanced load on the +5v and +12v rails (e.g a dual graphics card PC).
On a more positive note, the Silent Pro does exactly what it says on the tin. The combination of a 135mm fan along with excellent management of its speed depending on load and temperature makes the unit quieter than a mouse in slippers. For this reason alone, the Silent Pro 700w should certainly make its way onto the short list of those looking for a compact PSU to complement their HTPC or Silent PC build.
Expected to retail for around £94 over at stores such as Scan and Yoyotech, the Silent Pro 700w places itself right at the top scale for what we'd expect to pay for a unit of this wattage. Is it worth it? Well, if you're after an extremely silent, modular PSU then the answer is a definite YES. However, if you're after a PSU that will be predicable no matter what system config you throw at it, then probably no.
The Good
- Amazingly silent, even when pushed passed 700w load
- Silicon vibration dampeners shield the PC case from the PSU.
- Single +12v rail ensures that enthusiasts can make full use of every amp.
- Decent modular system with sexy looking cables.
- Rock solid +3.3v rail
- High level of efficiency under most load levels.
- Compact size suitable for small cases and some HTPC's.
The Mediocre
- Relies on balanced power consumption over the +5v and +12v rails for best results.
- Silicon gaskets on our sample unit had a tendency to fall off.
The Bad
- Nothing.
Overclock3D Silence Award
Thanks to Cooler Master for making this review possible. Discuss this review in our forum.