Comparison NZXT Kraken X63 vs NZXT Kraken X53

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.

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.

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.

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.

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.

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.

Type of power connector for the water pump.

— 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.

— 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.

— SATA. The SATA power connector will come in handy if all free 3pin and 4pin connectors are occupied on the motherboard.

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.