Cooler Master Silencio S400 Review

After two more Micro-ATX test objects were recently put to the test with the Cooler Master Masterbox MB400L and Kolink Citadel RGB Mesh, another model from Cooler Master is now following. The Cooler Master Silencio S400 is kept very discreet, arrives at the customer with a viewing window and insulated front or side panel. Everything else about the detailed test can be found on the following pages.

The Cooler Master Silencio S400 was used for the test available in the version with a window and with a slot for optical drives. The buyer also has the choice between steel and glass side panels. The street price for the housing here is currently around 70 euros.


Scope of delivery & technical data

The scope of delivery is typical for a case in this price range. In addition to the necessary screws for the hardware, rails and rubber guides for mounting the drive as well as a couple of cable ties are included. Since the Silencio S400 allows two lid versions as a special feature, the scope of delivery includes an air-permeable and an insulated version of the magnetically adhering lid.


Cooler Master Silencio S400
Mainboard format (s) Mini-ITX, micro-ATX
designation S400
Form factor Mini tower
Price housing approx. 80 euros
Manufacturer homepage
Other key data
Drives 4 x 3.5 ”
4 x 2.5″
1 x 5.25 “




1x 120mm rear,
1x 120mm front2x 140mm, 2x 120mm front,
2x 140mm, 2x 120mm
1 x 120mm
Radiator support Front:
1x 280mm, 240mm, 140mm, 120mm
2x 140mm, 120mm
1x 120mm
max.CPU cooler height max.166mm glass / 167mm steel side part
max.GPU length 319mm
max. power supply length 140-325mm
Material housing Sheet steel, glass, plastic
Weight approx 6.5 kg
Dimensions 210 x 418 x 408 mm (W x L x H)
Others two pre-installed 120mm fans
front door opening direction changeable
removable 5.25-inch shaft
pre-installed insulation material
dust filter
color Black
(also available with steel side part)

Impressions outside

The Silencio S400 is visually very appealing but appears rather reserved in the design language. In terms of color, matt black determines the picture, and color accents are searched in vain. Presumably, the optics would also like to appear “quiet”. There are no frills on the case, but our version of the Silencio S400 has a glass side panel for a view of the hardware. If you don’t need to look at your own hardware, you can use the approximately 10 Euro cheaper version with a steel side panel.


As the name suggests, Cooler Master uses a “quiet” housing for the Silencio S400, which wants to impress with its insulated side panel and a front door including an insulating material, at least in terms of noise. Basically, it can be said that it is a miniature Cooler Master S600.



Nevertheless, you don’t do without adequate ventilation, because in front of the door, which, by the way, can also be changed from the stop, there are ventilation openings for the fans behind it. From the factory, a 120mm fan with a maximum of 1,400 rpm is installed in the front (another is in the rear) and is covered by an easily removable ventilation grille to protect it from dust and dirt.

As already mentioned, the door can also be moved to the other side by loosening two screws so that you can easily get to the front from the right. So that this makes sense, there is a 5.25 inch bay in the upper area, e.g. for optical drives, which makes a door really necessary.

Even if the manufacturer focuses more on a quiet system, the Silencio S400 offers modular lid covers, which magnetically stay securely in place. If you don’t install a fan in the upper area, you use the insulated plastic cover, if you use a water cooling or a fan in the cover, you can also use the enclosed perforated grille. Certainly, a compromise on the part of Cooler Master, because you can also use the Master Box NR400 or MB400L for open cooling because this is about maximum insulation. Visually, the models don’t really look much like each other.

On the back everything is the same, there are no special features or surprises here. The screwed-on slot brackets are positive; on the MB400L these still had to be broken out.

Impressions inside

The interior is also immediately familiar because the same tooling is also used in the above-mentioned MB400L or NR400 models, also offers additional rubber grommets for a nicer look, and has some mounting options for storage media despite limited space.


The sheet steel chassis of the Silencio S400 is solidly processed, I did not find any sharp edges or unclean workmanship. As already mentioned, there are two 120mm PWM fans in the S400 which are allowed to rotate at up to 1,400 rpm and are supposed to provide the necessary airflow. If that’s not enough, you can add 120mm in the front or switch to two 140mm fans, but you have to remove the 5.25-inch drive bay. In the rear, there is a fan space for 120mm fans, which is already occupied. There is space in the lid for two 120mm or two 140mm fans. So you have enough space for a 240 or 280mm AiO water cooling, for example.

If you don’t want to install an optical drive in the Silencio S400 or need more space for more complex cooling solutions, you can easily remove the installation slot. If you want to use this, you can look forward to tool-free assembly, because the drive is held by an easily movable lock.

The right side is covered by an insulated side part, which with the additional acoustic material leaves a very solid impression and reveals the back when removed. Cooler Master has provided the S400 with enough space on the “hidden” side to be able to lay the cables neatly and the lower area offers not only the installation space for the power supply but also a more modular hard disk slot. This can accommodate up to three 3.25 inch drives, for this purpose the case comes with decoupled drive rails.


The case rests on four rubberized and generously dimensioned feet, which also keep enough space to allow the power supply to suck in enough air. A dust filter that can be easily removed is also attached here for protection.

Hardware installation

The installation of the hardware is child’s play for experienced hardware hobbyists, which is also due to the simple but practical solutions on the part of Cooler Master. The spacers for Micro-ATX mainboards are pre-assembled at the factory and the cutout on the back of the tray helps with the assembly of the CPU cooler, which, by the way, can have a maximum height of 166mm for the glass side panel and the maximum for the steel side panel Build up 167mm.

With a little skill, three 120mm fans can also be accommodated in the Silencio S400, but the ODD cage must be removed and two screw fastenings dispensed with. The assembly itself is also kept practical, as the front can simply be pulled off and the fan slots free


Hard drives find their place in the lower part, a cage is housed in the power supply tunnel for this purpose, which accommodates 3.25-inch drives using the slide-in strips provided. These only have to be clipped into the drive and decouple the drive from the steel chassis, something that works well in practice.

Again, I liked the solution for mounting SSDs positively. Just screw four retaining lugs into the SSD by hand, then plug four rubberized receptacles into one of the four places in the housing and the SSD can find its place there. Totally simple and practical.

Installation took less than 15 minutes and the hardware is neatly packed into the Silencio S400. Even if it is a mini-tower, there is enough space to do the installation easily. You don’t have to break your fingers when laying cables. Our MSI RX580 radiator can easily be accommodated in the S400, graphics cards can generally be up to 319mm long and thus higher-performance models such as an RTX 3080 can be installed, you can see which models would fit in our overview:  Overview: Nvidia Geforce RTX 3080 Graphics cards

Installation of a water cooling

In addition to complex air cooling, water cooling can also find its place in the Silencio S400. 120 or 140 mm radiators do not pose any challenges for the case, larger versions such as 240 mm or 280 mm only fit if the holder for the optical drive is removed beforehand.

Our 280mm radiator from Alphacool then fits in the front or in the lid where the air-permeable panel must be attached.

There is no room for larger or thicker models in the S400 from Cooler Master because there is simply not enough space for the mainboard or in the front.


Test system presented

Our case tests are carried out according to a standardized principle. As usual, how we test can be found in our articles,  How We Test. In this way, it is possible to compare all test reports in the area of ​​housings.

Overall rating

The overall rating is a summary of all temperatures and measured values. In total, this results in a performance indicator about the cooling capacity of each housing. We are currently endeavoring to fill in the basis of comparison so that all values ​​determined are also about one another.

Brief evaluation

Since we have adjusted our test procedure a little with this test, our table still looks a bit clear, but we have also measured another model directly so that there is a comparison value at least for the beginning.  Even if the Q300L (test report follows) has a more airy design, it only has one fan and that is noticeable in the temperatures. The difference is particularly evident at maximum speed, also, there is the fan in the S400 with 1,400 rpm, in the Q300L the fan in the rear only manages to rotate at a maximum of 1,000 rpm, which means significantly less air transported.

Brief evaluation

At maximum speed, in comparison with the Q300L, the disadvantages of the two fast rotating fans from the S400 become apparent. These are of course louder in IDLE mode and even if the measurements suggest something different, the perceived volume on the S400 is more pleasant than on the Q300L because it appears more muted. But the direct comparison is not really fair, a fan with 1,000 rpm against two fans with 1,400 rpm and then from the same company, had to be reflected in this way. That the maximum volume under load turns in favor of the S400 is easy to explain. Due to the better airflow of the two fast-rotating fans, the graphics card does not have to turn so high, it levels off at 65% fan speed and the overall system is therefore significantly quieter than the Q300L,

Brief evaluation

If the fan turns at only 800 rpm, the S400 pulls the short straw. Even if two fans are used, the case is too much sealed off and heats up faster than the airy Q300L, which feels like a frame made of holes. Here the CPU cooler and the graphics card cooler have to intervene more and thus rotate faster, which is reflected in the overall volume. However, this is still very pleasantly muffled, although the noise development is not annoying even if it is audible under load and is perceived as background noise. Although the Q300L is measured quieter, it appears louder because every sound arrives unfiltered, including a slight clacking of the fan bearings, higher sound waves from the graphics card cooler, in a subjective hearing comparisonitis in any case “more disturbing”. The insulation mats installed in the Silencio S400 are effective here. Without the closed lid with the perforated cover, the temperatures in the housing drop by 2-3 degrees as the warm air can simply rise upwards. But the volume increases audibly and the effect of the S400 is somewhat lost. Since the housing is an insulated variant, I will not deal with this topic any further.

Temperature measurement

To show the thermal capabilities of housing, we have documented two load scenarios or rather two ways of looking at them. Basically, the combination of Furmark  (@  1024 x 768px  – non-fullscreen) +  Prime95 “Custom”  (with 8 threads, further setting) is operated simultaneously for the tests, which, in turn, represents a very good mix of system utilization and practical relevance.

  • Measurement 1: Maximum speed
  • Measurement 2: 800 rpm (the value is set in the mainboard BIOS)

This process is now operated for  20 minutes,  recording the MAX value over the 20 minutes and, in a separate process, the  Delta T  value, i.e. the difference between the measured value and the room temperature. After completing the measurement process, the values ​​are read from AIDA 64. The unit of measurement is logically set to degrees Celsius. Of course, the method used is not immune to measurement tolerances, which means that fluctuations in the range of 0.5 degrees Celsius in the measured temperatures are possible.

Brief evaluation

The larger S600 had already shown in our test that the Silencio series is hot-headed. The same applies to the smaller S400. The slowly rotating fans create a very low airflow, which pushes the hardware to its limits, on hot summer days this could also lead to crashes. Since we operate the built-in hardware at the limit and this is seldom the case in everyday life, the GPU and CPU are loaded at 100% over a longer period of time, the values ​​should also be viewed as such. The values ​​can still be classified as high, with an additional fan in the front or perhaps in the rear turning it a little faster, improvements should be easy to achieve. Especially in this “closed” housing, the removal of warm air is more of a problem,

urze evaluation

What the built-in fans in the Silencio S400 can do, they show impressively at full speed. With a full 1,400 rpm, the temperatures drop by an average of 7.5 degrees, which clearly underlines the importance of a powerful airflow in a completely closed housing. The M.2 SSD in particular, which really does not have an easy time of it, is installed directly behind/under the graphics card, benefits from it because there is also an airflow at this point and the graphics card itself does not heat up as much due to the cooler one Air or the faster removal of the warm-up. The Q300L does not benefit that much from this, as only one fan with 1,000 rpm is installed and it is only 200 revs faster now.


Actually, I could adopt the conclusion of my colleague, who examined the ATX version in the form of the Silencio S600, because my findings coincide with the Silencio S400 I tested. I liked the Silencio S400 a lot, which is mainly due to the chic visual impression, which not only looks valuable but also confirms it haptically. Everything looks well thought out, even small things such as the changeable door hinge or an SD card reader have been thought of. The insulated parts together with the glass side panel also leave a good acoustic impression.

The pure performance is also okay in my opinion, the two pre-installed fans with their maximum 1,400 rpm deliver enough air to cool the built-in hardware. Nevertheless, you always make a compromise with a sound-optimized case when it comes to temperatures. Because these are quite high at low fan speed and, depending on the configuration, could be problematic in summer, but need not be. At the time when every fan can be controlled automatically via the mainboard, that is also the lesser evil. Because even if the volume increases in the case, the S400 knows how to filter it well and emit it into the environment in a less disruptive way.

With currently around 70 euros for the version with a glass side panel, the case is fairly paid for. You get a good quality of workmanship, a modern and chic look and you can let the built-in hardware operate quietly. The fact that there are only two USB ports and the temperatures are sometimes too high are too few points of criticism to not recommend the Cooler Master. So the Cooler Master Silencio S400 receives a buy recommendation from me.

Cooler Master General Summary

Cooler Master To summarize, we see that it has very good features in terms of design, price and performance. Cooler Master, which has given a successful performance compared to its competitors in this segment, has not received any serious complaints from its users until now and has given its users confidence with maximum positive feedback. With the Cooler Master 2-year warranty, it continues to support any problem after the sale and does not suffer the user.

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Installation of the Product is Extremely Simple. You can set it up easily with the included Guide.

Has no known chronic problems.

Yes, they say they are generally satisfied.

The minimum warranty period is 2 years.

You can buy it from sites like amazon, ebay.

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