Comparison Seasonic FOCUS GX FOCUS GX-750 vs Corsair RMx Series CP-9020179-EU

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").

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.

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.

A standard for power supplies that supplements the ATX specifications regarding power supply along the 12 V line. Introduced into use since the time of the Intel Pentium 4 processor. In the first series of the standard, the +5 V line was mainly used; from version 2.0, the +12 V line was introduced to fully power the components computer. Also in the second generation, a 24-pin power connector appeared, used in most modern motherboards.

The version of the EPS12V standard that the power supply complies with. The EPS12V standard was created primarily for high consumption PCs (with a power of more than 700 W, see "Power") and entry-level servers. Such power supplies have a 24-pin plug for the motherboard and an 8-pin processor power connector (sometimes more than one, see “MB / CPU Power” for more details). They are also more reliable than ATX12V. They are compatible with most ATX standard motherboards, however, in older motherboards, there may be problems with matching connectors, so this issue should be clarified separately (however, to solve this problem, in some power supplies, parts of the plugs are made removable, which allows them to be reduced if necessary to the dimensions of the connectors on the motherboard).

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.

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.

The maximum values of current and power that the PSU can provide on individual power lines.

The power line can be simply described as a pair of contacts for connecting a particular load; one of these contacts is “ground” (with zero voltage), and the second has a certain voltage with a plus or minus sign, this voltage corresponds to the voltage of the power line. In this paragraph, it is + 3.3V (such power is present in 20- and 24-pin connectors for motherboards, in SATA power connectors and some other types of connectors).

In general, power and currents are rather specific parameters that the average user rarely needs — mainly when connecting high-power components such as video cards, as well as when starting a PSU without a computer to power other electronics (for example, amateur radio stations). It is also worth mentioning that the sum of the maximum powers on all lines can be higher than the total output power of the PSU — this means that all lines cannot operate at full power at the same time. Accordingly, when the PSU is fully loaded, some of them will produce less power than the maximum possible.

The maximum current that the PSU is capable of issuing + 5V to the power line. For more information about power lines in general, see "+3.3V". Also note here that + 5V power, in addition to connectors for motherboards (for 20 and 24 pins), is also found in Molex and SATA plugs, as well as some other specific types of connectors.