If you want to build a PC you will need a power supply and you better spend your time choosing a good quality one adjusted to your needs. If you are new in the world of building yourself your own PC you may think that the power supply is one of the “non-important” components. But you should ask yourself: why there are models starting at as low as $20 and others models reaching the $200?


If you see errors, misleading information, or you just don’t agree with me I would really appreciate your comments so we all can improve this post together. Try to be nice with each other and be collaborative.

How To Choose The Best PSU


Most of the PSU’s manufacturers have different quality ranges, so we can’t say that a specific brand is good or bad.

You should avoid buying cheap power supplies because it is in the lower price ranges where you can be scammed if you don’t know what are you buying. Hopefully, you will learn here what to look for in a power supply.

The electronic components wear over time, particularly when they are used out of their optimal workload. This will cause a premature wear, and this could mean that your power supply could last a couple of months before stop working or even burning your other computer’s components.


In order to overclock your CPU or GPU, you will need a power supply that provides a stable 12V output. That’s because when you overclock any component of your computer, you are actually increasing the component’s voltage itself and so you need the most stable voltage stream possible to ensure the components get the power they need.

So, if you want to overclock your CPU or GPU without risking your other component’s integrity you need to spend more money on a more powerful PSU, with better capacitors and better construction materials.


The indicated PSU’s power by the manufacturer is not the power that it really provides. To know what is the real power we need to multiply the power supply’s profit factor by the value provided by the manufacturer.

Good quality power supplies usually have a PF (profit factor) of 80% or more. The remaining 20% is dissipated as heat, but you pay for it anyway as you are still consuming it. So, the higher the PF, the lower our electricity bill and more efficient the power supply will be.

You won’t find any PSU with a PF of 100%. The top high-end models may reach the 90 or 92 percent at full load. And you won’t see any of these models for less than $100.

Another efficiency indicator is the PFC (Power Factor Correction) type. It can be Active or Passive. You DO NOT want a passive power supply in your life. If someone tries to sell you one, just run away and don’t look back.

The passive models have usually a PF of 0.5, so the 50% of the power consumption is wasted due to heat loss. They also generate more noise, both electrical and environmental.

And to finish, they don’t have any kind of electronic component protection, which can be really dangerous for your whole computer’s integrity. Nasty thing indeed.

To check how efficient a power supply is, you have to check what kind of 80 Plus certification has. There are different levels. The higher the certification level, the higher the overall PSU quality and efficiency:

  • 80 Plus (white): 80% efficiency
  • 80 Plus Bronze: 81% – 85% efficiency
  • 80 Plus Silver: 85% – 89% efficiency
  • 80 Plus Gold: 88% – 92% efficiency
  • 80 Plus Platinum: 90% – 94% efficiency
  • 80 Plus Titanium: 91% – 96% efficiency

Geographic Situation And Continued Use

This is probably the most subtle pitfall where most people get caught.

When using a power supply in warm areas the power consumption is increased.

Why? Because a higher environmental temperature lowers the PSU’s power factor. And that could cause an unexpected low performance.

This can also be caused by playing GPU-intense games during hours. The heat is accumulated inside the PC tower lowering the PSU’s power factor.

This is most common than you may think. And this can happen simply because you have a poor internal PC airflow or because you have the tower cornered under your desktop.

In warm areas, the PSU power factor is reduced, increasing the internal temperatures and reducing its efficiency.

A decreased power factor also higher the power consumption to keep the needed power levels of your computer.

So keep this in mind in order to choose the proper PSU’s wattage. Power supplies deliver their maximum efficiency at 40-60% load, so add a 50% watts to the value you had from the last step.

If you keep the load inside the 40-60% range, the components will suffer way less which means that the useful life of your power supply will increase dramatically.

It’s so important to keep the workload low to guarantee the highest efficiency and avoid problems related to noise, short useful life, breaking other components, heat problems…

Heavy-duty Protections

As I said before, good PSUs are expensive because they have a better efficiency and more protections. Having a PSU with proper protections can save your entire computer from an irreversible catastrophe.

These are the most common heavy-duty protections:

  • OVP: Over Voltage Protection
  • UVP: Under Voltage Protection
  • OCP: Over Current Protection
  • OPP: Over Power Protection
  • SCP: Short Circuit Protection
  • OTP: Over Temperature Protection

Calculating Our Power Needs

Now you know what affects the PSU’s performance and why there are different range prices.

The next step is to calculate the power you will need to feed your computer.

For example, let’s imagine that you are building a computer that consumes 400 watts at full workload.

Add a 40% of your full workload consume. Depending on your geographic situation you will want to add a safety margin, let’s say 50 W.

So, for this example, we would need a 400 + 400*0.4 + 50 = 610W  PSU.

With a 600W – 650W power supply your workload will be always between the 40%-60% range, which is the range our PSU should be to maximize its performance and durability.

Easy, right?

Buying Guide

I wouldn’t buy a power supply for less than $30 because of the mid/long term problems they can cause.

These are the reasons by which I don’t recommend them:

  • They are passive PFC models. This means that they consume x2 the power that is providing to the computer. This results in a higher electricity bill, higher temperatures, and more noise
  • They doesn’t have the proper protections against power surges. That could end up damaging your entire computer

Standard – From $30 to $55

Depending on your CPU + GPU combination you will have different power requirements. If you have an Intel + Nvidia/AMD build, you will need a 400W power supply. On the other hand, if you prefer an AMD CPU, you will need a 600W power supply.

It is hard to find a model that meets the quality standards while keeping a low budget but the 80 PLUS “White” Certified EVGA 500 W1 clearly nails it.

This is without a doubt the best PSU in the market to be used in tight budget gaming computers.

The EVGA 500 W1 features a quiet and auto-regulable fan which makes it pretty silent, which is something rare to find in this price range.

Other than that, it also has heavy-duty protections (that you won’t definitely find in any other PSU for this price) including UVP (Under Voltage Protection), OPP (Over Power Protection), and SCP (Short Circuit Protection).

One of the most important parts of every computer build is the power supply unit. Whenever possible, try to get a good quality unit, at least with 80+ Bronze certification.

One of the best options for mid-budget builds (more than $600) in terms of price/quality ratio is the Corsair CX 450M, a semi-modular unit from one of the best PSU manufacturers. It’s worth every penny.

  • 80+ Bronze certification
  • Up to 85% energy efficiency means less heat generation and lower energy bills
  • 0.99 Active Power Factor Correction provides clean and reliable power
  • Dimensions: 150mm x 86mm x 140mm

Gaming – From $55 to $100

The following models are the recommended power supplies if you can afford them because you will get rid of all the problems associated to the bad quality components like low efficiency, low durability, ambient noise and electrical noise.

Master Race – From $100

In this price range you will find power supplies that are usually needed in high-end builds (overclocked CPUs or two GPUs). You could also be interested in these models if you want specially silent power supplies or if you live in extreme warm areas.


Added Products

  • March 19, 2018: Corsair VS 450, Corsair VS 550
  • March 12, 2017: Corsair RM550x, Corsair RM750x, Corsair RM1000x

Removed Products

  • March 12, 2017: Corsair RM550, Corsair RM750, Corsair RM1000


How did you find this guide? Did you have in mind all the aspects discussed in this guide prior to buying your current PSU? Do you think is worthwhile spending your money on this component?

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Adrian Benavides

I've been always an avid gamer with limited resources. This led me to learn how to build the best gaming computers within tight budgets. Now, I want to share the knowledge I've acquired over the years with the world!

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