Review PSU Corsair CS850M

Review PSU Corsair CS850M

After about a year after testing the model Corsair CS650M we return to the study of the products of this series. Since that time, in the range of Corsair two new models of 750 and 850 watts. And if CS750M looks exactly like CS650M, with a minimum difference, the Corsair CS850M made in the case of larger length of 160 mm and is equipped with a fan size 140 mm, which hints at the changed temperature and acoustic characteristics, which we will explore later.

Packaging BP framed in white and green colors with black elements. A medium-sized box made of cardboard of sufficient thickness, carrying handle is missing. From packaging CS650M, differences are only in size.

The power supply has a black housing with a matte finish with a rather small, but well-perceived texture. Fingerprints on this coating are almost invisible. The length of the body, as we noted earlier, is about 160 mm, additionally need at least 15 mm for the supply wires to the power source, so installation should not rely on the installation size of 180 mm.


All necessary parameters are specified on the housing power supply in full. For power bus + 12VDC stated value of 849.6 Watts. The ratio of the power bus + 12VDC and full power is 0.9995, which is a great indicator.

The length of the wires and the number of connectors

In this power, supply is used so-called modular wiring connectors for power components inside the system unit. This design allows you to remove unused wires, freeing up space and give a more accurate view of the interior of the system unit.

Review PSU Corsair CS850M

The number of connectors is quite sufficient for the system unit average, but taking into account the announced capacity would like to see a greater number of connectors SATA Power – of the order of 9-12 pieces on the three cords. But the number of peripheral connectors clearly excessive – compared with CS650M have an additional power cord with four such connectors. Why do you need it, remains a mystery, while instead it would be possible to add a third cable with connectors SATA Power, which would have made a set of connectors is much more balanced and relevant power of the product.

Cable length is sufficient for comfortable use in buildings full tower size and more overall overhead power supply. In buildings up to 60 cm with power supply wiring length must also be sufficient: the power connector to the processor – about 67 cm. Thus, with the majority of modern buildings should be no problems.

Cooling system

The power supply has a fan HA1425L12F-Z with a nominal speed of rotation of 1600 rpm, but the fan is marked at 1800 revolutions per minute, so it’s most likely a special modification produced to order Corsair. The fan is based on hydrodynamic bearings and manufactured by Dongguan Honghua Electronic Technology. Fan connection – detachable, two-wire.

Review PSU Corsair CS850M

Major semiconductor elements are mounted on two radiators medium size with a thickness of the base about 4 mm, radiators are sufficiently competent design since they combine a relatively low aerodynamic resistance and increased dissipation area in the upper part by placing several plate members at intervals directly beneath the fan. Moreover, in this construction the plates are oriented vertically, thus increasing heat transfer. It is also important that a radiator is not created “dead” zones in which there is a problem with the cooling components.

Semiconductor components independent DC converters channels + 3.3VDC and + 5VDC located on the daughter printed circuit board and additional heat sinks are not, which is quite typical for the power supply with active cooling.

When the output of the power supply from the standby mode to start the fan applied the voltage of 12 V, and after the successful promotion of the fan control system switches to the control mode based on temperature. When the fan stops him periodically served starting 12 V as long as he does not start. Such implementation of the control circuit reduces the risk of stopping the fan, as well as simplifies the choice counterparts for replacement, as in this case is not required to seek a fan with a starting voltage lower than 5 V. The fans of this size are quite common in retail. The minimum supply voltage of the fan is about 4.75 when controlling the speed of rotation according to the temperature.

The power supply has a high-voltage capacitor Rubycon, and low-voltage – mainly Teapo. In standby power circuit – NCC and Capxon. In principle, everything is quite in line with modern trends to the average person products. Complete set Japanese capacitors can be seen mainly in high-end products, and only in very rare cases – the average person.

Testing power supply

In this case, no problems, stress values deviate slightly from the nominal value.The first step is to test the operation of the power supply at maximum power for a long time. This test allows you to confidently verify performance PSU.

The next step is the construction of the instrumental test characteristics (tures) and submitting it to limited by the maximum capacity of the bus 5 3.3 & on one side (on the ordinate) and the maximum capacity of the bus 12 on the other side – on the abscissa. At each point of the measured value of the voltage indicated by a color marker, depending on the deviation from the nominal value.

It is necessary to clarify that in the presence of abnormalities within three percent of the power supply parameters can be considered to be at a good level.

During the next phase of testing, we measure the voltage is AC, which is connected to the power supply is analyzed, with the latter on a permanent power. Based on the data calculated parameters determining the efficiency and effectiveness of power supply.In this model throughout the tested range of power are no deviations of more than five percent. In a typical power distribution channels, deflection voltage values on the main channels do not exceed two percent. Via + 12VDC and all deviations within one percent of the nominal current carrying capacity of the channel is high.
We compared the values obtained with the previously tested PSU Thermaltake Moscow 850, which also has a certificate of 80Plus Gold. At higher Corsair CS850M efficiency in the range of 200 to 600 W, whereas in the range up to 200 watts and 600 watts to 800 the difference is minimal, while a maximum power efficiency is slightly higher at 850. The last Moskva Thermaltake dissipates 60 watts when the load power is 600 W that is less than Corsair CS850M (640 W). Thus, Corsair CS850M demonstrates high rates of profitability.The cost of the model is at a very good level. 60 W power supply dissipates the power in the order of 640 watts. At maximum power, the power supply dissipates 96 watts. Performance is not a record, but in this parameter, this model is quite competitive compared with classmates who have a certificate 80Plus Gold.

Review PSU Corsair CS850M

With regard to light duty operation and unloaded mode, then all also quite adequately: in sleep mode by itself consumes PD less than 0.5 watts, and in an active mode – about 10 watts. The last parameter does not stand out among the classmates of similar capacity.

We also measure the inrush current at idle with a fully charged capacitors.Efficiency PSU is at a very good level. According to our measurements, the efficiency of the power supply reaches a value exceeding 90% in the power range from 200 to 800 watts, and in the range of from 200 to 500 – over 92%. The maximum recorded value was about 93% at a power of 300 to 400 watts. Simultaneously, the efficiency at 50 W was about 80%.

In terms of absolute value, the inrush current is not small, so the ability to use cheap low-power UPS is a big question. As for the comparison with power supply units of the same capacity, the performance of the inrush current from the power supply far from the maximum registered by us, which also can be evaluated positively.

At the request of chitateteley and now we measure the maximum power that the power supply is able to give through one video card power connector PCI-E. During this testing phase power supply is loaded with channel + 12VDC through only one slot PCI-E, with the burden of channels + 3.3VDC and + 5VDC is set at about 1 A per channel.

During testing, the power supply was connected with two connectors, which are located on a single power cord. This result demonstrates the ability of BP to supply any power of modern graphics cards.

Thermal conditions

Noise measurementThermally loaded capacitors is low (60 degrees or less) over the entire power range. Thus, the power supply is well suited for operation under high load and has a good margin temperature. At low power ratings cooling performance even more redundant, since the temperature of the capacitors very close to the ambient temperature.

In preparing this material, we used the method of measuring the noise power supply, which still has the status of experimental. The power supply is located on a flat surface fan up over it at a distance of 0.35 meters placed measuring the sound level meter microphone Octave Eco-110A, which is measured and the noise level. The load power supply is carried out using a special stand, having a silent mode. During the noise measurement unit operation is performed on a constant supply of power for 20 minutes, then the noise level measurement is performed.

A similar distance to the object of measurement is closest to the desktop layout of the system unit with installed power supply. This method allows to estimate noise power unit under severe conditions from the viewpoint of a small distance from the noise source to the user. By increasing the distance to the noise source and the appearance of additional obstacles, having a good sound-reflecting ability, the noise level at the control point will also decrease, leading to improvement in the overall acoustic ergonomics.

In CS650M noise in this range it was much lower, but most users will hardly feel the difference, as the level of operating noise of the system unit and the ambient noise in the room exceed the noise Corsair CS850M.When working in a range of up to 350 W power supply and including noise is very low – in the range of 25 dBA at a distance of 0.35 meters. Noted source with noise at night, it is possible unless with a small (less than a meter) range, and only if, especially listening, and turning off all other appliances and close the windows.

On power 500 W Noise increases slightly, and can already be interpreted as a low (below level) for the premises during the day.

When operating at 750 W noise level of the model is close to the value at the location BP in the near field. At greater distances the power supply unit and placing it under the table in the body with the bottom PSU location such noise can be interpreted as being below average. During daylight hours, in a residential area source with a similar noise level is not too noticeable, especially from a distance of one meter or more, and the more it will be barely noticeable in offices, as background noise in offices are usually higher than in a residential area.At night, a source with the noise level will be clearly visible, it will be difficult to sleep next. This noise can be considered comfortable when working at the computer.

When a load of 850 W power supply noise reaches the border ergonomic 40 dBA subject placed on a desktop, that is at the location of the power supply in the near field with respect to the user. This noise value can be described as high.

Thus, from the viewpoint of ergonomics, this acoustic model provides comfort when the output power range of 750 W, demonstrating a range of up to 275 W in the present low noise.

We compared the values obtained with the previously tested PSU Thermaltake Moscow 850. According to information received, the noise level Corsair CS850M significantly lower on all power ratings compared to Thermaltake Moscow 850, although the latter is not at all noisy.

We also appreciate the noise electronics power supply, because in some cases it is the source of unwanted overtones. This stage of testing is carried out by determining the difference between the noise level in our laboratory with the included power supply and switched off. If the value obtained is within 5 dB, no deviations in the acoustic properties of BP no. When a difference of more than 10 dBA, as a rule, there are some defects that can be heard from a distance of about half a meter.

At this stage, the sound level meter measurement microphone is located at a distance of about 40 mm from the upper surface of the PSU, as at large distances noise measurement electronics is very difficult. The measurement is performed in two modes: the standby mode (STB, or Stand by) during operation to a load power supply, but with the fan forcibly stopped.

In this case, noise is minimal electronics, the main contribution to the overall noise power unit brings the fan is running.

Operation at elevated temperature

At the final stage of tests, we decided to test the power supply at elevated ambient temperature, which was 40 degrees Celsius. During this test phase space volume of about 8 cubic meters heated to the designated temperature after which temperature measurement capacitors and the power supply noise.

Corsair CS850M demonstrated stable operation at maximum power and at elevated to 40 degrees ambient temperature. The noise level under similar conditions at the maximum expected capacity increased to 46 dBA (t. E. 6 dB of the initial value), and in the power of 125 W noise level grew by only 2 dB from the initial value and amounted to 26 dBA.

With regard to the condenser temperature, it was 62 degrees (an increase of 10 degrees) at the maximum power and 43 degrees (an increase of 16 degrees) during power of 125 watts. Thus, even under such stringent conditions thermally loaded capacitors not of concern.

Evaluation of consumer qualities

Consumer Quality Corsair CS850M are at a very good level. Among the shortcomings can be noted ergonomics is not the best set of connectors, and noise at low load could be even lower. But in the actual operation of the vast majority of users of such noise is unlikely to notice.It should be noted very decent length of wire that will be in demand owners dimensional buildings. Acoustic ergonomics BP is very decent. Profitability in this model is also at a good level and is consistent with the best representatives of the cohort of PD are certified 80Plus Gold. Finally, the electrical characteristics and no major complaints, as deviations from the nominal voltage under load is small, and the long-term work at full capacity is not satisfactory even in the case of operation at elevated ambient temperature.


Technical and operational characteristics of Corsair CS850M are at a good level, which contribute to the high load capacity of the channel + 12VDC, high efficiency, low thermally loaded, the fan on the hydrodynamic bearings with long service life. Capacitors only partially Japanese manufacturers, but in the case of the new product is a significant effect has not. So you can count on a fairly long life power supply unit even at high constant loads. Mention very decent acoustic ergonomics of the model.


Review PSU Corsair CS850M updated: May 7, 2015 author: John Malkovich