Which power supply pays the most

PC power supply: everything to consider before buying!

Without it, the computer stays off: COMPUTER BILD gives helpful tips on buying a PC power supply unit.

The PC power supply, like the processor, RAM and hard drive, is one of the essential computer components. With its many connections, it supplies all components with power. If the power supply breaks, a replacement must be found quickly. In this case, the defective electricity dispenser provides the first clues to quickly find a comparable model. If you want to assemble your PC yourself, you should consider further points. The watt specification alone is not decisive. COMPUTER BILD reveals which seal you should look out for and which other properties are important.

First of all: That is what a current PC power supply unit has to offer

  • Provide enough power: Power supplies are available in different performance classes depending on the area of ​​application. It usually starts at 400 watts.
  • Provide sufficient connections: The model of desire should have enough connections for all built-in components (graphics card, memory, etc.).
  • Score with extras: Removable and sheathed cables (cable management and sleeve) as well as (semi-) passive operation are among the extras, but they cost a lot of money.
  • Be prepared for the future: The optimal power supply unit is prepared for component changes, so it offers free connections and power reserves (in watts). This is usually the case with branded devices

Why does a PC need a power supply at all?

Alternating current comes from the socket, but the PC components work with direct current. This results in the main task of the power supply unit: It has to convert alternating current into direct current. In addition, every component of the computer needs a certain voltage, some even need several voltages at the same time. The power supply ensures that every part receives the necessary voltage. To do this, it distributes the current to different cables with different voltages.

How much power should the power supply have?

That depends on the area of ​​application! A simple office computer without a dedicated graphics card needs a 300 watt power supply. A gaming PC, on the other hand, should have at least a 550 watt power supply, because a powerful pixel accelerator and a nimble processor thirst for power. High-end systems with more than one graphics card may need a power supply with 750 watts or more to satisfy the hunger for energy. In addition to the total wattage, the current intensity on the individual lines and the total output of all lines (combined power) determine the possible uses of a power supply unit. The manufacturers provide details on their websites and on a sticker on each individual power supply unit.

You enter your configuration into the be quiet! which then determines a suitable power supply unit.

There are calculators on the Internet that recommend suitable power supplies based on individual configurations. The power supply calculator from be quiet !, which only suggests suitable devices from the manufacturer, is popular. Alternatively, the Enermax calculator with finer setting options is recommended. The wattage helps you to estimate which power supply unit (possibly from another manufacturer) is required for your PC. Brands with a good reputation include Corsair, Enermax, be quiet! and Seasonic.

What happens if the power supply is too weak?

Then the computer could crash - for example when playing a game or playing a video. Because the components consume so much power that the power supply unit can no longer reliably supply them with the required voltage.

How do power supplies differ?

  • Size: Not every power supply unit fits into every housing. The manufacturers indicate the respective size as a form factor. The most widespread is the ATX standard. However, case and power supply manufacturers do not always strictly adhere to the norm. Therefore, when purchasing a new power supply unit, you should carefully compare the dimensions of the case with those of the slot in the case of your computer.
  • Connections and cable length: There should be enough and sufficiently long cables for peripherals. The current minimum is two PCI-Express connections (6 + 2 or 8 pin), four S-ATA connections for hard disks, SSDs and optical drives, and two Molex connections for older drives, expansion cards and adapters. A 24-pin ATX connector and an 8-pin connector to supply the motherboard, the processor and the main memory are mandatory. As a user of a small or medium-sized housing, you usually do not need to worry about the cable lengths; Only in so-called big towers should you study the manufacturer's information beforehand so that you do not experience any nasty surprises during installation. By the way: Some power supply manufacturers offer models to which the supplied power cables are simply connected to the power supply via a plug connection, often referred to as cable management. This saves unnecessary cables, reduces the clutter in the PC case and improves air circulation.
  • Operating noise: In modern power supplies there is usually a fan with a large diameter (120 millimeters or more), the only task of which is to keep the components in the power supply cool. Until the early 2000s, the propellers were responsible for cooling the entire PC, and sometimes went to work accordingly. Temperature sensors, optimized fans etc. ensure that the background noise from the power supply units remains low during operation - according to the well-known manufacturers who usually state the volume on their websites.

If a power supply manufacturer wants to adorn itself with one of the coveted 80-plus seals, the corresponding device must have a certain degree of efficiency in defined load scenarios, which is specified by the Plug Load Solutions.

What else makes a good power supply?

  • Efficiency: This value indicates what proportion of the energy absorbed by the power supply unit goes directly to the components in the computer. The worse the efficiency, the more power the power pack converts into heat. For example, if the efficiency is 60 percent, 40 percent of the energy taken from the socket is lost. This increases the power consumption and the computer has to be cooled more expensively. Good power supplies achieve an efficiency of 80 percent and more. They can be recognized by the 80 plus sign, which defines the efficiency in three (with 80 Plus Titanium four) load scenarios.
  • Voltage stability: Power supplies must reliably supply the computer with power. If the voltages are unstable, the PC may crash. This is why the output voltages are constantly regulated in all power supplies. However, the technology used (switched-mode power supply) causes network disturbances, so-called harmonics. This is why there are line filters in all power supplies to reduce this interference. The manufacturers call this PFC ("Power Factor Correction"). A distinction must be made between the passive and active variants, with the latter having established itself due to its better effectiveness.
  • Security: A high-quality power supply unit has various protective functions. They ensure that the power supply unit switches off as quickly as possible in the event of overvoltage (OVP), overcurrent (OCP), overtemperature (OTP) and short circuit (SCP). These functions not only protect the power supply, but also the expensive components in the PC. All power supplies sold in the European Union must bear the CE mark. Important: Despite these protective functions, you must never unscrew a power supply unit. Because even if the mains plug is pulled, very high voltages can still be stored in the power supply unit.

Comparison of PC power supplies

With the knowledge you have gathered, it is now easy to find a suitable power supply unit for your PC. The PC power supply comparison is a good place to go to find out about the performance, features and noise level of the components. The table shows devices from Asus, Corsair and be Quiet! juxtaposed. The comparison winner is the top model and the price-performance winner usually convinces with a decent range of functions at an affordable price.

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