Efficiency
Efficiency, in this case — the ratio of the power of the power supply (see "Power") to its power consumption. The higher the efficiency, the more efficient the power supply, the less energy it consumes from the network at the same output power, and the cheaper it is to operate. Efficiency may differ depending on the load; the characteristics can indicate both the minimum efficiency and its value at an average load (50%).
It should be noted that compliance with one or another level of 80PLUS efficiency directly depends on this indicator (for more details, see "Certificate").
Fan size
The diameter of the fan(s) in the power supply cooling system.
The large diameter allows to achieve good efficiency at relatively low RPMs, which in turn reduces noise and power consumption. On the other hand, large fans are more expensive than small ones and take up a lot of space, which affects the dimensions of the entire PSU. We also emphasize that a small fan is not yet a sign of a cheap power supply — quite advanced models can also have such equipment, in order to reduce dimensions.
As for specific diameters, the smallest value that can be found in modern consumer-grade PSUs is
80 mm. The most popular option is
120 mm, this size gives good efficiency and a relatively low noise level at a reasonable price and dimensions. Larger diameters are somewhat less common —
135 mm and
140 mm.
Fan bearing
The bearing is the piece between the rotating axle of the fan and the fixed base that supports the axle and reduces friction. The following types of bearings are found in modern fans:
— Sliding. The action of these bearings is based on direct contact between two solid surfaces, carefully polished to reduce friction. Such devices are simple, reliable and durable, but their efficiency is quite low — rolling, and even more so the hydrodynamic and magnetic principle of operation, provide much less friction.
— Rolling. They are also called "ball bearings", since the "mediators" between the axis of rotation and the fixed base are balls (less often — cylindrical rollers) fixed in a special ring. When the axis rotates, such balls roll between it and the base, due to which the friction force is very low — noticeably lower than in plain bearings. On the other hand, the design turns out to be more expensive and complex, and in terms of reliability it is somewhat inferior to both the same plain bearings and more advanced hydrodynamic devices. Therefore, although rolling bearings are quite widespread nowadays, however, in general, they are much less common than the mentioned varieties.
— Hydrodynamic. Bearings of this type are filled with a special liquid; when rotated, it creates a layer on which the moving part of the bearing slides. In this way, direct contact between hard surfaces is avoided and friction is significantly reduced compared to previous...types. Also, these bearings are quiet and very reliable. Of their shortcomings, a relatively high cost can be noted, but in fact this moment often turns out to be invisible against the background of the price of the entire system. Therefore, this option is extremely popular nowadays, it can be found in cooling systems of all levels — from low-cost to advanced.
— Magnetic centering. Bearings based on the principle of magnetic levitation: the rotating axis is "suspended" in a magnetic field. Thus, it is possible (as in hydrodynamic ones) to avoid contact between solid surfaces and further reduce friction. Considered the most advanced type of bearings, they are reliable and quiet, but expensive.
MB/CPU power supply
The number and type of connectors provided in the PSU to power the motherboard or processor.
This parameter is written as the sum of several numbers, for example, "24+4". The first number in such an entry means the number of contacts in the connector for powering the motherboard; in the vast majority of cases, this is just 24, since modern motherboards use a 24-pin connector as standard. The second number describes the socket for powering the processor; most entry-level and mid-range CPUs use 4-pin power, but powerful chips may require 8-pin power. There can be several 4- or 8-pin connectors — based on powerful high consumption processors.
A separate case is the blocks of the "24 (20 + 4)" format. They have two separate plugs — 20 pin and 4 pin, which allows you to power both 24-pin motherboards and older 20-pin motherboards from such power supplies. At the same time, such models do not provide a separate power supply for CPU — it is powered only through the socket, and the 4-pin plug cannot be connected to any other components except the motherboard.
Now on the market there are PSUs with such power supply for the motherboard:
24 pin (20+4),
24+4 pin,
24+8(4+4) pin,
24+8+8(4+4) pin.
SATA
The number of SATA power connectors provided in the PSU.
Nowadays, SATA is the standard interface for connecting internal hard drives, and it is also found in other types of drives (SSD, SSHD, etc.). Such an interface consists of a data connector connected to the motherboard, and a power connector connected to the PSU. Accordingly, in this paragraph we are talking about the number of SATA power plugs provided in the PSU. This number corresponds to the number of SATA drives that can be simultaneously powered from this model.
MOLEX
The number of Molex (IDE) connectors provided in the design of the power supply.
Initially, such a connector was intended to power peripherals for the IDE interface, primarily hard drives. And although the IDE itself is completely obsolete today and is not used in new components, however, the Molex power connector continues to be installed in power supplies, and almost without fail. Almost any modern PSU has at least
1 – 2 of these connectors, and in high-end models this number can be
7 or more. This situation is due to the fact that Molex IDE is a fairly universal standard, and with the help of the simplest adapters, components with a different power interface can be powered from it. For example, there are Molex - SATA adapters for drives, Molex - 6 pin for video cards, etc.
Floppy
The presence of at least one Floppy power connector in the PSU.
Initially, this connector was intended to power floppy disk drives, hence the name. It is also known under the designation "mini-Molex". Anyway, this standard is generally considered obsolete, but it is still used by some specific types of components, and therefore continues to be used in power supplies.
Cable system
The cable system used in the power supply. According to this parameter,
modular, semi-
modular and non-modular devices are distinguished, here are their features:
— Not modular. The classic version of the design, used in computer power supplies from the very beginning and not losing popularity to this day. The wires in such systems have a non-detachable design, and additional cables are not provided for connection. As a result, the user has to deal with only those cables that the manufacturer provided, without the ability to remove or replace them (the only modifications available are the installation of additional accessories such as an extension cord or splitter). Because of this, such PSUs are less convenient than modular and semi-modular ones: their wires are often excessively long, and some of them are not used at all, while such an “economy” further clutters up the case, worsening air circulation and cooling efficiency. On the other hand, these shortcomings can be reduced to almost zero with careful selection of the PSU and careful wiring; and non-modular systems themselves are distinguished by reliability and at the same time low cost. It is because of these features that they are most common nowadays.
— Modular. Systems in which each cable is made detachable; special sockets are used for fastening wires. Thanks to this design, you can optimally organize the space inside the PC —
...for example, remove unnecessary wires so that they do not interfere with air circulation in the system unit; replace a cable that is too long with a shorter wire (or vice versa); swap cables, etc. At the same time, modular systems are noticeably more expensive than non-modular ones, while they are considered somewhat less reliable due to the presence of "weak points" in the form of removable cable mounts.
— Semi-modular. A kind of compromise between the options described above: some of the wires in such power supplies are made non-removable, some are equipped with modular mounts. This makes it possible to partially combine the advantages and compensate for the disadvantages of the two systems: semi-modular PSUs are less expensive and more reliable than modular ones, and at the same time more convenient than non-modular ones. Usually, in systems of this type, the most important wires have a non-removable design, which are almost guaranteed to be used when assembling a PC, and secondary cables are equipped with removable mounts and can be removed if not needed. However, the specific features of a semi-modular PSU should be specified separately.+12V1
The maximum current that the PSU is capable of delivering to the first power line is + 12V.
For more information about power lines in general, see "+3.3V". Here it is worth mentioning that 12 V is the most popular voltage among computer power connectors. It is used in almost all such connectors (with a few exceptions), and some plugs (for example, additional PCI-E power for 6 or 8 connectors) use only 12-volt lines — and in the + 12V format. And the division of + 12V power into several separate lines is used for safety purposes — in order to reduce the current flowing through each individual wire, and thus prevent excessive load and overheating of the wiring. However, some manufacturers do not specify the maximum current for individual + 12V lines and give only a general value in the characteristics; in such cases, this number is indicated in this paragraph.