How do Power Supply Ratings Work? Why is it Important?

80 Plus platinum rated PSU

Choosing the right power supply unit (PSU) for your build can be quite tricky, especially with so many options out there. That’s why the 80 Plus rating system was created to rate a PSU’s efficiency and reliability. So how do power supply efficiency ratings work?

Power supply efficiency is rated using the 80 Plus certification program. An 80 Plus certified power supply must have an efficiency of at least 80% at 20%, 50%, and 100% loads. The ratings include Bronze, Silver, Gold, Platinum, and Titanium, each showing a higher minimum efficiency rating.

Let’s learn more about power supply efficiency, how it’s rated, and what it can do for the overall health and longevity of your PC. 

What are Power Supply Ratings?

Power supply rating measures how efficiently a power supply converts the AC power it receives from the outlet into the DC power used by the computer’s components. It is usually measured in percentage. The higher it is, the more efficient the power supply is. 

The efficiency rating is typically measured using the 80 Plus certification program. This industry-standard certification measures the energy efficiency of a power supply.

The certification is awarded based on the power supply’s ability to deliver a specified output power while staying within a certain range of efficiency. A power supply must demonstrate at least 80% energy efficiency at 20%, 50%, and 100% of its rated output power to achieve 80 Plus certification.

80 plus rating for a power supply

The most common certifications are:

80 Plus Rating10% Load20% Load50% Load100% Load

Here’s a complete list of power supplies and their wattage and 80 Plus rating. 

80 Plus vs. Generic PSUs

Generic Power supply with no rating

Generic PSUs are unbranded or low-quality power supplies with no specific efficiency standards. They may use cheaper components and lack features such as voltage regulation, which can lead to instability and reduced performance.

These power supplies may also have lower efficiency ratings, meaning they consume more power and generate more heat. This can negatively impact your system’s performance and lifespan.

80 Plus certified PSUs are better than generic PSUs due to their higher efficiency, reliability, and performance. They’re designed to deliver at least 80% energy efficiency, reducing energy consumption and lowering your utility bills.

They also feature high-quality components, advanced voltage regulation, and improved cooling, ensuring stable and consistent performance. So by choosing an 80 Plus certified PSU, you get a better, more efficient, and reliable power supply, ensuring the stability and longevity of your computer system.

Does Power Supply Efficiency Really Matter?

Yes. Power supply efficiency is an important factor to consider when choosing a power supply for your computer. The efficiency of a power supply is a measure of how well it converts the electrical power it receives from the outlet into the power used by the computer’s components.

A PSU with a high-efficiency rating, such as 80 Plus Bronze, Silver, Gold, or Platinum, indicates that it’s more efficient at converting AC power to DC power. This results in lower electricity bills and less heat generation.

Other Things to Consider When Buying a PSU

The power supply won’t increase the frame rate or improve aesthetics. But it’s just as important as the rest of the PC. In fact, it could make or break your system’s long-term health. So when buying one, there are several things other than efficiency to consider:


Make sure the PSU has enough wattage to power all the components in your system. A higher wattage PSU is usually recommended for systems with high-end components, such as a gaming graphics card. Here’s a power consumption guide of the best gaming GPUs so you know how many watts each use. 

You can also use a wattage calculator to help you determine how much power your PC needs. Choose a PSU with around 10% to 15% more watts than the total power consumption to account for any future upgrades or changes in the system. It is also important to note that the power supply efficiency also depends on the load. The higher the load, the lower the efficiency.


Reputable brands are more likely to produce high-quality products that are built to last. They use better components and manufacturing processes to produce more reliable PSUs with fewer issues. So it will last longer and provide more stable power to the computer’s components, reducing the risk of system instability, random shutdowns, and permanent damage to the components.

They’re also more likely to provide good customer support. If a problem arises with the PSU, it will be easier to contact the manufacturer and get a replacement or resolve the problem. This is especially important if the PSU is covered under warranty and you need to make a claim.

So choose a reputable brand with a good track record for producing high-quality PSUs. Brands such as Seasonic, Corsair, and EVGA are generally considered to be reliable.


Some PSUs come with modular cables. This allows you to connect only the cables you need, giving you greater control over cable management and reducing clutter inside your case. This can improve the overall appearance of your build, as well as improve airflow, which can lead to better cooling performance.

Protection Features

Look for protection features like over voltage, over current, short circuit protection, and temperature control. These features protect against power surges, voltage spikes, and overloading, which can damage or destroy your components and cause data loss or corruption.

By ensuring that your PSU has these features, you can prevent costly and time-consuming repairs and help ensure the longevity of your computer.


A noisy PSU can produce a humming or whining sound, which can be distracting and disrupt your work or entertainment.

High noise levels can also indicate that the PSU is struggling to deliver the power it’s designed to provide. So it’s important to check the noise level of the power supply unit. The lower the noise level, the better it is.

Form Factor

This determines the shape and size of the PSU and must match the specifications of the computer case in which it will be installed.

If it doesn’t match the computer case, it won’t fit properly and won’t be usable. ATX is the most common form factor, but there are others like SFX, TFX, and CFX.

What Can Happen with a Faulty Power Supply?

A faulty power supply can cause a number of problems with your computer, including:

  • System instability: A faulty power supply can cause fluctuations in voltage and current, leading to system crashes and other stability issues. This can cause your computer to freeze, reboot unexpectedly, or even shut down completely.
  • Data loss: If your power supply is not providing a stable power source to your hard drive, it can cause data corruption or loss.
  • Damage to components: A faulty power supply can also cause damage to other components in your computer, such as the processor, graphics card, or memory. This damage can be irreversible and may require costly repairs or replacement of the damaged components.
  • Overheating: A faulty power supply may not be able to provide enough power to keep your computer cool, which can lead to overheating and damage to your components.
  • Fire hazard: In some cases, a faulty power supply can cause a fire, which is a serious safety concern.

It’s essential to keep an eye out for any signs of malfunction. Such signs include your computer shutting down unexpectedly, experiencing frequent crashes or instability, or observing any strange noises or smells coming from your computer. If you suspect that your power supply is faulty, it’s best to turn off and unplug your computer immediately and have it checked by a professional.

Final Thoughts

Power supply efficiency ratings are crucial to modern computer systems and should not be overlooked. Measuring the amount of energy lost during the conversion process helps us determine the effectiveness and efficiency of a power supply unit. 

Opting for a high-efficiency PSU can help you save on electricity bills, reduce heat and noise, and extend the lifespan of other components. In short, a good power supply is the foundation of a stable and reliable computer system. So when it comes to building or upgrading, make sure to choose a high-quality and efficient power supply that meets your needs.

Lucas Coulson

I first got into building my own computer when I was around 12 or 13. The first computer I had ever built didn't work. So I kept researching to figure what I did wrong. I really enjoyed researching, learning, and building computers, so I decided to turn it into an online business, and here I am.

Recent Posts