Fan size
The diameter of the fan(s) used in the cooling system.
In general, larger fans are considered more advanced than smaller ones: they allow you to create a powerful air flow at a relatively low speed and low noise level. On the other hand, a large diameter means large dimensions, weight and price. As for specific figures,
40 mm and
60 mm models are considered miniature,
80 mm and
92 mm are medium,
120 mm and
135 /
140 mm are large, and even
200 mm fans are found in the most powerful
case systems.
Min. RPM
The lowest speed at which the cooling fan is capable of operating. Specified only for models with speed control (see below).
The lower the minimum speed (with the same maximum) — the wider the speed control range and the more you can slow down the fan when high performance is not needed (such a slowdown allows you to reduce energy consumption and noise level). On the other hand, an extensive range affects the cost accordingly.
Max. air flow
The maximum airflow that a cooling fan can create; measured in CFM — cubic feet per minute.
The higher the CFM number, the more efficient the fan. On the other hand, high performance requires either a large diameter (which affects the size and cost) or high speed (which increases the noise and vibration levels). Therefore, when choosing, it makes sense not to chase the maximum air flow, but to use special formulas that allow you to calculate the required number of CFM depending on the type and power of the cooled component and other parameters. Such formulas can be found in special sources. As for specific numbers, in the most modest systems, the performance
does not exceed 30 CFM, and in the most powerful systems it can be up to 80 CFM and even
more.
It is also worth considering that the actual value of the air flow at the highest speed is usually lower than the claimed maximum; see Static Pressure for details.
Static pressure
The maximum static air pressure generated by the fan during operation.
This parameter is measured as follows: if the fan is installed on a blind pipe, from which there is no air outlet, and turned on for blowing, then the pressure reached in the pipe will correspond to the static one. In fact, this parameter determines the overall efficiency of the fan: the higher the static pressure (ceteris paribus), the easier it is for the fan to “push” the required amount of air through a space with high resistance, for example, through narrow slots of a radiator or through a case full of components.
Also, this parameter is used for some specific calculations, however, these calculations are quite complex and, usually, are not necessary for an ordinary user — they are associated with nuances that are relevant mainly for computer enthusiasts. You can read more about this in special sources.
MTBF
The total time that a cooling fan is guaranteed to run before it fails. Note that when this time is exhausted, the device will not necessarily break — many modern fans have a significant margin of safety and are able to work for some more period. At the same time, it is worth evaluating the overall durability of the cooling system according to this parameter.
Min noise level
The lowest noise level produced by the cooling system during operation.
This parameter is indicated only for those models that have capacity control and can operate at reduced power. Accordingly, the minimum noise level is the noise level in the most “quiet” mode, the volume of work, which this model cannot be less than.
These data will be useful, first of all, to those who are trying to reduce the noise level as much as possible and, as they say, “fight for every decibel”. However, it is worth noting here that in many models the minimum values are about 15 dB, and in the quietest — only 10 – 11 dB. This volume is comparable to the rustling of leaves and is practically lost against the background of ambient noise even in a residential area at night, not to mention louder conditions, and the difference between 11 and 18 dB in this case is not significant for human perception. A comparison table for sound starting from 20 dB is given in the "Noise level" section below.
Noise level
The standard noise level generated by the cooling system during operation. Usually, this paragraph indicates the maximum noise during normal operation, without overloads and other "extreme".
Note that the noise level is indicated in decibels, and this is a non-linear value. So it is easiest to evaluate the actual loudness using comparative tables. Here is a table for values found in modern cooling systems:
20 dB — barely audible sound (quiet whisper of a person at a distance of about 1 m, sound background in an open field outside the city in calm weather);
25 dB — very quiet (normal whisper at a distance of 1 m);
30 dB — quiet (wall clock). It is this noise that, according to sanitary standards, is the maximum allowable for constant sound sources at night (from 23.00 to 07.00). This means that if the computer is planned to sit at night, it is desirable that the volume of the cooling system does not exceed this value.
35 dB — conversation in an undertone, sound background in a quiet library;
40 dB — conversation, relatively quiet, but already in full voice. The maximum permissible noise level for residential premises in the daytime, from 7.00 to 23.00, according to sanitary standards. However, even the noisiest cooling systems usually do not reach this indicator, the maximum for such equipment is about 38 – 39 dB.
Socket
Socket - processor connector - with which the corresponding cooling system is compatible.
Different sockets differ not only in compatibility with a particular CPU, but also in the configuration of the mounting place for the cooling system. So, when purchasing a processor cooling system separately, it is worth making sure that it is compatible with the socket. Nowadays, solutions are mainly produced for the following types of sockets:
AMD AM2/AM3/FM1/FM2,
AMD AM4,
AMD AM5,
AMD TR4/TRX4,
Intel 775,
Intel 1150,
Intel 1155/1156,
Intel 1366,
Intel 2011/2011 v3,
Intel 2066,
Intel 1151/1151 v2,
Intel 1200,
Intel 1700.
Heatsink size
The nominal size of the radiator provided in the water cooling system.
The radiator provides cooling of the heated coolant coming from the cooled components of the system. It most often works on the principle of a cooler — that is, it consists of the actual radiator and one or more fans. The size of the radiator is indicated by one number — by the largest dimension, length. And the width (on which the working area and, accordingly, efficiency depends) can be determined based on the length. The fact is that radiators use fans of two diameters — 120 and 140 mm; if there are several such fans, they are installed in a row. This means that the length of the structure will necessarily be a multiple of the fan diameter — 120 or 140 mm, and the width will correspond to this diameter. For example, a
120mm or
140mm product would have the same width and one fan, while a
240mm product would have two 120mm fans.
The described features lead to the fact that a larger size does not necessarily mean a more advanced design. So,
a 360mm or even
420 mm radiator with three small fans can have the same or even lower efficiency than a
280mm model. In addition, we recall that larger fans with the same performance are slower, and therefore quieter.
...Also, the size of the radiator must be taken into account when looking for a seat in the case for it. Be aware of the width as well: 140mm fan heatsinks are usually not compatible with 120mm fan heatsink slots. So, a 140 mm model will not fit in a 240 mm (2x120 mm) socket, and 280 mm (2x140 mm) will not fit under 360 mm (3x120 mm), although formally the size seems to be enough in both cases.