Air flow direction
The direction in which the active cooler (see "Type") airflow exits.
This parameter is relevant primarily for models used with processors, but the options can be as follows:
—
Sideways (scattering). Operation format typical for coolers of the so-called tower design. In these models, the fan is mounted perpendicular to the substrate in contact with the processor, due to which the airflow moves parallel to the motherboard. This ensures maximum efficiency: the heated air does not return to the processor and other system components, but is dissipated in the case (and almost immediately goes outside if the computer has at least one case fan). The main disadvantage of this option is the large height of the structure, which can make it difficult to place it in some system units. However, in most cases this point is not fundamental — especially when it comes to a powerful cooling system designed for an advanced system with a performant "hot" processor. So, it is side dissipation that is the most popular option nowadays — especially in coolers with a maximum TDP of 150 W and higher (although more modest models often use this layout).
—
Down (to the motherboard). This format of operation allows you to "lay" the fan with a heatsink flat on the motherboard, significantly reducing the height of the entire cooler (compared to models using side blowing). On the other hand, this format of
...work is not very efficient — after all, before dissipating through the case, hot air again blows over the board with the processor. So nowadays, this option is relatively rare, and mainly in low-power coolers with an acceptable TDP of up to 150 W. And you should pay attention to such models mainly when there is little space in the case and a small cooler height is more important than high efficiency.Max. TDP
The maximum TDP provided by the cooling system. Note that this parameter is indicated only for solutions equipped with heatsinks (see "Type"); for separately made fans, the efficiency is determined by other parameters, primarily by the air flow values (see above).
TDP can be described as the amount of heat that a cooling system is able to remove from a serviced component. Accordingly, for the normal operation of the entire system, it is necessary that the TDP of the cooling system is not lower than the heat dissipation of this component (heat dissipation data is usually indicated in the detailed characteristics of the components). And it is best to select coolers with a power margin of at least 20 – 25% — this will give an additional guarantee in case of forced operation modes and emergency situations (including clogging of the case and reduced air exchange efficiency).
As for specific numbers, the most modest modern cooling systems provide TDP
up to 100 W, the most advanced —
up to 250 W and even
higher.
Max. RPM
The highest speed at which the cooling system fan is capable of operating; for models without a speed controller (see below), this item indicates the nominal rotation speed. In the "slowest" modern fans, the maximum speed
does not exceed 1000 rpm, in the "fastest" it can be up
to 2500 rpm and even
more.
Note that this parameter is closely related to the fan diameter (see above): the smaller the diameter, the higher the speed must be to achieve the desired airflow values. In this case, the rotation speed directly affects the level of noise and vibration. Therefore, it is believed that the required volume of air is best provided by large and relatively "slow" fans; and it makes sense to use "fast" small models where compactness is crucial. If we compare the speed of models of the same size, then higher speeds have a positive effect on performance, but increase not only the noise level, but also the price and power consumption.
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.
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.
Heatpipe contact
The type of contact between the heat pipes provided in the heatsink of the cooling system and the cooled components (usually the CPU). For more information about heat pipes, see above, and the types of contact can be as follows:
—
Indirect. The classic version of the design: heat pipes pass through a metal (usually aluminium) base, which is directly adjacent to the surface of the chip. The advantage of such contact is the most even distribution of heat between the tubes, regardless of the physical size of the chip itself (the main thing is that it should not be larger than the sole). At the same time, the extra piece between the processor and the tubes inevitably increases thermal resistance and slightly reduces the overall cooling efficiency. In many systems, especially high-end ones, this drawback is compensated by various design solutions (primarily by the tightest connection of the tubes with the sole), but this, in turn, affects the cost.
—
Direct. With direct contact, the heat pipes fit directly on the cooled chip, without an additional sole; for this, the surface of the tubes on the desired side is ground down to a plane. Due to the absence of intermediate parts, the thermal resistance at the places where the tubes fit is minimal, and at the same time, the radiator design itself is simpler and cheaper than with indirect contact. On the other hand, there are gaps between the heat
...pipes, sometimes very large — as a result, the surface of the serviced chip is cooled unevenly. This is partly offset by the presence of a substrate (in this case, it fills these gaps) and the use of thermal paste, however, in terms of uniformity of heat removal, direct contact is still inevitably inferior to indirect contact. Therefore, this option is found mainly in inexpensive coolers, although it can also be used in fairly performant solutions.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.