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.
Pump size
The dimensions of the pump that the water cooling system is equipped with.
Most often, this parameter is indicated for all three dimensions: length, width and thickness (height). These dimensions determine two points: the space required to install the pump, and the diameter of its working part. With the first, everything is quite obvious; we only note that in some systems the pump simultaneously plays the role of a water block and is installed directly on the cooled component of the system, and it is there that there should be enough space. The diameter approximately corresponds to the length and width of the pump (or the smaller of these dimensions if they are not the same — for example, 55 mm in the model 60x55x43 mm). Some operating features depend on this parameter. So, the large diameter of the pump allows you to achieve the required performance at a relatively low rotation speed; the latter, in turn, reduces the noise level and increases the overall reliability of the structure. On the other hand, a large pump costs more and takes up more space.
Pump MTBF
The MTBF of a liquid cooling pump is the approximate amount of time after which the pump is likely to fail. This figure is not 100% accurate and actual pump life may be less or longer than advertised, depending on usage. Nevertheless, this indicator is convenient for comparing different models with each other: more time between failures and in fact means greater reliability and durability.
Pump power source
Type of power connector for the water pump.
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3-pin. The three-pin power connector on older motherboards does not allow you to control the speed of the water pump motor in liquid cooling systems. At the same time, the pump always works in the maximum performance mode. Fresh "motherboards" are able to change the voltage on such connectors, thereby providing a change in engine speed.
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4-pin. When using a 4pin power connector, it is supposed to control the speed of the pump motor using pulse-width modulation. A voltage of 12 V is applied to it with pulses. By changing the duration of the pulses, you can accurately set the speed of the water pump motor.
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SATA. The SATA power connector will come in handy if all free 3pin and 4pin connectors are occupied on the motherboard.
Dimensions
General dimensions of the cooling system. For water systems (see "Type"), this paragraph indicates the size of the external radiator (the dimensions of the water block in such devices are small, and there is no need to specify them in particular).
In general, this is a fairly obvious parameter. We only note that for case fans (see ibid.), the thickness is of particular importance — it directly depends on how much space the device will take up inside the system unit. At the same time, it is customary to refer to
fans with a thin case for models in which this size does not exceed 20 mm.