Cooling system
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1 fan. The most common option. The power of such a system is quite enough to cool the power supplies, including Above average and relatively inexpensive. On the other hand, fan operation creates noticeable noise, especially in low-cost power supplies with small diameter fans (see "Fan Diameter").
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2 fans. The second fan is usually installed in powerful power supplies, for which the power of one fan is not enough. The price for such efficiency, in addition to increased cost, is an increased noise level.
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Semi-passive cooling. A function that allows you automatically turn off the PSU cooling system in situations where the load on the power supply is low and heat dissipation is reduced. It is found only in models with active cooling. Recall that systems of this type are more efficient than passive ones, but they consume additional energy and create noise during operation. Accordingly, at a light load, when intensive cooling is not required, it is more reasonable to turn off the fans — this saves energy and reduces the noise level.
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Passive(radiators). Compared to fans, heatsinks have a number of advantages: for example, they do not create noise at all and do not require their own power supply (thus reducing overall power consumption). On the other hand, they are much less efficient, as a result — the power
...of power supplies with passive cooling does not exceed 600 watts. In addition, these PSUs are quite expensive.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.
PCI-E 8pin (6+2)
The number of PCI-E 8pin (6+2) power connectors provided in the PSU design.
Additional PCI-E power connectors (all formats) are used to additionally power 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). In PC components, there are two types of such connectors — 6pin, providing up to 75 W of additional power, and 8pin, giving up to 150 W. And the 8pin (6 + 2) plugs used in power supplies are universal: they can work with both 6-pin and 8-pin connectors on the expansion board. Therefore, this type of plug is the most popular in modern PSUs.
As for the quantity, on the market you can find models
for 1 PCI-E 8pin (6 + 2) connector,
for 2 such connectors,
for 4 connectors, and in some cases —
for 6 or more. Several of these plugs can be useful, for example, when connecting several video cards — or for a powerful high-performance video adapter equipped with several PCI-E additional power connectors.
+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.
+5V
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.
+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.
+5Vsb
The maximum current that the PSU is capable of issuing + 5Vsb to the power line.
For more information about power lines in general, see "+3.3V". Specifically, the + 5Vsb line is used to power the computer electronics in standby mode, when the main and only task of the system is to respond to pressing the power button. This does not require high power, so this figure rarely exceeds 3A.
+12V
The maximum power that the PSU is capable of delivering to the + 12V power line.
See "Maximum current and power" for details on power lines in general. 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. So this indicator is one of the most important characteristics of any PSU.
Note that many power supplies have several separate + 12V power lines. In such cases, the total power is indicated here, which, usually, is divided equally between the lines.
+3.3V +5V
The maximum power that the PSU is capable of delivering on the + 3.3V and + 5V power lines.
See "Maximum current and power" for details on power lines in general. Here we note that the power lines + 3.3V and + 5V are used both in the general connector for the motherboard (for 20 or 24 pins), and in specialized plugs — in particular, the SATA power connector (both) and Molex (only +5V, in addition to +12V). The power of these lines is a rather specific parameter, rarely required in fact; it is usually the same for both voltages, so it is indicated in the general clause.
