Choosing a Computer Power Supply For Your Custom Build

The computer power supply (also known as the PSU) is an often-overlooked yet important part of your custom gaming PC. Without a power supply, your computer would just be a box full of metal and plastic without power. This article explains what you need to know about choosing a capable PSU for your computer.

In a PC, the computer power supply is the metal box usually located in the corner of the computer case. In many systems the power supply is visible from the back of the case because it contains the power-cord connector and the cooling fan. The main purpose of the power supply is to convert AC power from the mains to usable low-voltage DC power for the internal components of the computer.

The power supply gives out three different DC voltages to your computer, 12VDC, 5VCD, and 3VDC. These three voltages are used for different components in your system. For example, the 5VDC voltage powers the motherboard, voltage regulators, serial and parallel ports, and PCI and AGP ports.

How Much Power Do You Need?

Each power supply has a certain wattage based on their maximum output power. Common wattages range from 300W to 500W, although for a high-end gaming power supply wattages of 600W, 700W, and even 800W are common. Some units even go up to 1 kW of wattage, but this amount of power isn't neccessary for normal users.

For a typical gaming computer I would recommend at least 500W of power, although you may need more or less depending on your system. Note that even if a certain component lists its required wattage, it won't necessarily use that amount of power.


The computer power supply is a vital part of your computer and provides the power to the components in your system, and also cools your computer with a fan. It would be wise to get a decent quality PSU from a reputable brand that runs quietly so that you can rest easy at night knowing your gaming PC is being powered properly, and without having to worry about reliability problems or having to upgrade the PSU anytime soon.

If you're looking for specific recommendations on the best PSUs to buy right now for your new build in terms of quality, reliability, and value for money, see our recommended builds section.