The power supply unit is the backbone of any PC. It supplies the necessary power to run the electronic equipment inside your computer, such as GPUs, RAM, graphic cards, and video cards. While some people know which power supply unit is best for their PC, others don’t have a clue about it.

Most articles you find on the web are way too technical for a layman to understand. This article is an attempt to simplify the selection criteria of a PSU for you. We’ll discuss the 7 things to consider before choosing a PSU for your PC. So, let’s get started!

1. Wattage

The first and foremost consideration before buying a PSU is the total wattage requirement of your system and accessories. A normal PC consumes around 300 watts. Whereas a gaming PC can consume in the range of 600 to 1,000 watts. You can calculate the wattage of the system yourself.

The number of watts consumed by each piece, such as RAM or hard disk, is mentioned on it. All you need to do is add these numbers and check the total power consumption. Now that you know the total power consumption, let’s move on to the next step.

I’ll conclude this factor with the next one, as wattage and efficiency are closely connected to each other. You need to understand one to make sense of the other.

2. Efficiency and 80 Plus Rating System

Based on the materials and parts used in the construction of a PSU, their efficiency differs. An 80 Plus rating system is used to classify PSUs according to their efficiency. Here is a table to understand the 80 Plus rating system. This table shows the efficiency of each class against different load levels:


Load Levels





80 Plus





80 Plus Bronze





80 Plus Silver





80 Plus Gold





80 Plus Platinum





80 Plus Titanium





Now let’s combine this 80-plus rating system with the wattage of your system. The best rule for choosing the PSU wattage is my opinion, is to consider a 50% load scenario. Now, suppose the total requirement of your system is 300 watts. Then, you must choose a PSU capable of delivering 600 watts.

As a 600-watt PSU would deliver somewhere between 480 and 564 watts depending upon the 80-plus rating class you are choosing. On both ends, it will be safe to operate your PC.

3. Form Factor

The form factor is the next important thing to consider before buying a PSU. A form factor basically denotes the size and shape of the PSU. You must match the form factor of the new PSU with the old one to ensure that it will fit into the PC.

Thankfully the standards for form factor are universal. With ATX12V leading the way, you should still look into the form factor of your particular PC model.

4. Modular or Non-Modular Cabling

A non-modular power supply comes with fixed cables, and you don’t get to choose the cables. All you have to do is plug these cables into individual components. Modular PSU, on the other hand, comes without any fixed cables. You get to select the cables, thus a greater room for customization.

You have a third option of hybrid cabling as well. This is a combination of non-modular and modular cabling. But I don’t recommend it. Either you choose the cables, or you don’t. A hybrid or dual-cabling PSU will keep you in double mind, and you might end up hurting the PC.

5. Protection

The power supply unit is one of the two components in your PC that is connected to all pieces of hardware, the other one being the motherboard. Hence, it is necessary to ensure a certain degree of protection against current and voltage overflow.

You must look for options that have a built-in OVP (Over-voltage protection). This feature automatically shuts down the system in case of a voltage surge.

6. Fan Noise

I don’t know why but fan noise in PSUs is something that particularly annoys me. Plus, it goes on to show the poor build quality of the product. So, look for a PSU that offers quieter operation.

7. Allowance to Upgrade

The 50% load rule I discussed in the efficiency section will cover this factor as well. If you’re choosing a PSU for 50% maximum load conditions, then it will leave ample room for you to upgrade your PC further.

Final Word; 7 Things to Consider Before Choosing a PSU for Your PC

We have laid out the 7 things to consider before choosing a PSU for your PC in a systematic manner. The most important factors are listed before those with lesser importance. If you follow things in the mentioned order, the PSU selection process will become a lot easier.

We hope that you use this methodology to determine which PSU is best for your computer. Please leave down your comments to let us know your thoughts on this subject. We would love to hear from you!