Learn ASCII.jp SilverStone products, now can not ask the power supply unit to choose Iloch

　When it comes to homemade PC, it's good to choose convincing parts you like from a wide range of choices and assemble your own. Needless to say, flower-shaped components such as CPU and video cards, motherboards, memory, SSD and other components directly related to performance, PC shells and lighting components and so on, the key points that vary from person to person have also undergone great changes.

　Among these components, the important but less concerned one is the power supply unit. To be honest, many people choose on the basis of price, because as long as there is enough capacity, it will hardly affect the performance and appearance of the PC. However, even if the power unit is selected, there are many key points to check.

　In this report, for the beginners of PC who do not know how to choose the power unit, and those who are not aware of choosing the power unit so far, from the explanation of the basic part to the method of selecting the power supply capacity.

First of all, let's know the contents of the label on the power unit.

　As keywords related to the performance of the power unit, the words "power capacity" and "80PLUS" appear. First of all, let's understand these two key words that seem to know but accidentally don't know.

"Power capacity" the power capacity is a value indicating how much power the power unit can output. The unit is "W (watt)".

　The power supply unit plays an important role in transforming the AC 100V (AC input) of the socket into the DC voltage (DC output) used in PC. The maximum power that can be taken out after the transformation is the capacity of the power supply unit. Parts that are insufficient and consume a lot of power. Since high-performance CPU and video cards cannot be moved, the appropriate capacity needs to be selected.

　It should be noted that the PC uses-12V, + 3.3V, + 5V, and + 12V, each with an output upper limit. How much power can be output is written on the label of the power unit, so let's take the "SST-ET550-HG-Rev" of the SilverStone with 550W output as an example.

The output label affixed to the power supply unit. In this way, the power is recorded from input to output.

　The output is written as "DC OUTPUT", which records the maximum current that can flow through each voltage. By the way, the so-called "+ 5Vsb" refers to the standby power that can continue to be output even when the phone is turned off. The Wake On LAN (WoL) for connecting the power of the PC through the network, the power supply to the USB port, etc.

　The "MAX." "POWER" is electricity. Because the power is voltage × current, the simple calculation should be + 3.3V for 66W, 5V for 100W, but look at the label, only "110W" will be written in the middle. In addition, the voltages are written individually, why is there only a difference between + 3.3V and + 5V?

　The reason is simple: "the sum of + 3.3V and + 5V is 110W". Because the conversion sources of the two voltages are the same, it is limited to 110W, which is the upper limit of the conversion source.

　The section with "550W" written at the bottom, for the same reason, is smaller than the total power of each voltage, but this is the maximum output.

　Most of the power provided to CPU and video cards is borne by + 12V, which can be said to be the most important. SilverStone's "SST-ET550-HG-Rev" can output 540W of 550W at + 12V, so it can be said to be easy to use for heavy load and tolerance.

　As a reference, we will also introduce the same series of 650W and 750W labels. By the way, although it is easy to mistake for a beginner, the power capacity of each unit is always the maximum amount of electricity that can be output and does not always consume that power. Some people may think that if it is 550W and 750W, the power consumption of 750W is greater, but what is related to the power consumption is the conversion efficiency described later.

Unlike 550W, the output current of + 12V is increased from 45A to 53A. From this change, we can also see that + 12V is valued.

When it reaches 750W, not only + 12V is further promoted to 62A, but also 3.3V and + 5V to 22A respectively.

"80PLUS" certification "80PLUS" certification is the level of output at which conversion efficiency can be applied under a load of 20%, 50%, 100%. The higher the grade of the power supply, the higher the conversion efficiency, which has the advantages of restraining useless heating and power consumption.

　The condition value of efficiency varies according to the grade, and the lowest "80PLUS Standard" has nothing to do with the load, which is more than 80%, but in the highest "80PLUS Titanium", 20% load is more than 92%, 50% load is more than 94%, and 100% load is more than 90%. In addition, only the Titanium increases by more than 90% at 10% load.

Needless to say, the body of the power supply unit also has the logo of "80PLUS" on the package. SST-ET550-HG-Rev is a 80PLUS Gold certified power supply.

80 PLUS ranking and conversion efficiency list. The conditions of efficiency will also change according to the load, but the efficiency is the highest at 50% load.

　The power conversion efficiency does not affect the performance of PC, but has a great impact on power consumption.

　For example, suppose you have a PC that consumes 300W of power. If the conversion efficiency is 100%, the power required to run the PC is 300W, but if the conversion efficiency is 90%, 333W is needed, and if it is 80%, 360W is needed.

　As to where the extra electricity is going, most of it is released by the power unit as heat. It is not only wasteful, but also may be the cause of the temperature rise in the PC shell, so the conversion efficiency is expected to be high.