PC Power Supplies Guide: Keeping All PCs Powered!

Whether you are building a new computer system or replacing an old unit, it is important to purchase an efficient power supply. The power supply unit you purchase will affect the performance and reliability of your computer system, so it is essential that you choose the right one. This guide will explain why PC power supplies are so important and what you should look for when you are shopping for one.

pc power supply unit
High quality power supply units will provide clean and stable power, helping your computer to run longer. [Image credit]

What is a power supply unit?

Power supply units convert AC power from the mains socket, to useable low-level DC power which the components of computers run on. Power supply units are usually built to conform to the ATX form factor. This suggests that power supply units should be interchangeable with different components inside a computer. ATX power supplies are also designed to turn on and off using a signal from the motherboard, and provide support for computer functions like standby modes.

Power supplies are usually rated based on their maximum output power. For personal desktop computers this usually ranges between three hundred to five hundred watts, however gaming computers with multiple processors may require a higher level unit, which can go up to two kilo watts.

Read also: The PC Won’t Turn On – Basic Troubleshooting for Power Loss

PC power supplies buying guide

When it comes to purchasing power supply units for your computer, the price you pay reflects the quality of the product. Gaming computers and other powerful systems require reliable power, so it is essential to buy the best quality supply you can afford. The power supply unit is the heart and soul of your PC and is the unit which keeps it healthy and running to its full potential. The more CD drives, hard drives and other elements you add to your computer, the more strain it puts on your power supply. If you do not have a high quality power supply you will find that your system suffers from inconsistent levels of power and hardware failures.

A high quality power supply unit will decrease the amount of noise your computer makes. The noise you hear is caused by the fan, which is a necessary component used to cool down your power supply. New, efficient and powerful supplies will deliver regulated power, meaning that the fan will not need to work as hard to cool down the supply, so you will find that it makes much less noise.

Read also: How to Fix an Overheating Laptop (6 Simple and Effective Tips)

When purchasing a power supply for your PC it is essential that you make sure it is compatible. Some power supplies require a special adapter plug which links them to the motherboard. If you are unsure, it is best to check the computer manufacturer’s guidelines or seek help from an expert.

Technical terminology

As a buyer it is sometimes difficult to understand the terminology used by manufacturers. When purchasing a power supply for your PC look out for the phrase ‘mean time between failures’ as this figure will represent the average time a power supply is expected to perform before it fails. It is also essential to purchase a power supply unit that has overvoltage protection. This prevents signals from being received if the voltage exceeds the limit of the power supply.

power supply unit for pc
Power supply units help to keep your computer running efficiently. [Image credit]

All PC power supplies have a maximum load current which dictates the greatest current it can safely handle. The maximum load current enables consumers to calculate the amount of power their supply can provide and how many devices it will be able to support. The efficiency level of the power supplies is another important factor. This value is expressed as a percentage and presents the rate of power going into the supply against the rate coming out of it. The higher the percentage the better, as the more efficient your supply is, the less heat it will produce, keeping your computer running safely for longer.


Despite their importance, PC power supplies are often the elements of a computer which are ignored and forgotten about. Most shoppers do not check the power supply unit when they are purchasing a new computer, even though it will determine how efficiently a computer runs and how long it lasts. If you are thinking of purchasing a low cost computer it is important to check its power supply, as they are often fitted with cheap, low quality components. It may be worth purchasing a separate power supply to increase the lifespan of your system.


  1. Ludwig Ericsson
  2. Darnell Jackson
    • Peter Lee
  3. Praveen Bhardwaj
    • Peter Lee
  4. Sarah Park
    • Peter Lee
  5. Aayna
  6. Fatima
  7. Ryan Hudson