Power
The output power of the power supply, in other words, is the maximum power that it is capable of delivering to the system. For the computer to operate efficiently, the power supply must be greater than the total power consumption of the system at maximum load. The latter can be calculated by summing the power of individual components, however, in general, for office configurations
, about 400 W —
450 W is considered sufficient, for medium gaming — about
600 W(
500 W,
550 W,
650 W,
700 W,
750 W), and for the top ones —
power of 800 W and above (
850 W,
1000 W and even
more than 1 kW).
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.
ATX12V version
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.
EPS12V version
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).
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.
PCI-E 6pin
The number of 6-pin (6pin) PCI-E power connectors provided in the power supply.
Such connectors are used for additional power supply of those types of internal peripherals for which 75 W is no longer enough, supplied directly through the PCI-E socket on the motherboard (video cards are a typical example). The 6-pin connector on the power supply additionally provides another 75 W — thus, when using this connector, it becomes possible to connect boards with a power consumption of up to 150 W.
Note that some video cards have several connectors for additional power at once. Thus, the PSU can provide both
one PCI-E 6pin plug, and
two such connectors. However, in general, this type of plug is used quite rarely — this is due to the spread of a more convenient and versatile 8pin connector in the “6 + 2” format, which can be used both as six- and eight-pin (see below for more details).
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.
Braided wires
The presence of a braid in the complete wires of the system unit — for all or at least for some.
This feature has a positive effect on reliability, making the wire as resistant as possible to bending, abrasion, strong pressure and other similar influences; it also provides additional protection against accidental contact with sharp objects (for example, when repairing a PC). The disadvantages of braided wires, in addition to increased cost, are also increased thickness and greater rigidity than similar cables in conventional insulation. This can create some difficulties in organizing space inside the system unit.
+3.3V
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.