How to choose a Power Supply

How to choose a Power Supply?

One of the most crucial parts of any PC is the power supply, which gives it the energy it needs to run. For your information, many inexperienced constructors often overlook the significance of this component since they are unsure how to choose a power supply.

However, the power-supply unit (PSU) converts the high-voltage AC into a lower-voltage DC for the computer’s components, such as the CPU, graphics card, RAM, and others.

The power supply doesn’t directly enhance the PC’s appearance or gaming frame rates. Instead, it plays a crucial part in keeping the system operational by transmitting at maximum strength. An inadequate power source might generate more heat and perform at a lower efficiency level than a high-quality power supply.

A broken power-supply might also harm the computer’s parts. This article might assist you if you’re having problems like that or wish to get a new power supply. To make a better decision, be sure to read all the relevant information provided below.

Be sure to check out our many other buying guides, including the Best Graphics Card under $300Best CPUs for GamingBest Motherboard for Ryzen 7 5800x, and Top 10 Best Gaming Mouse

How to Choose a Power Supply: First Verify Reliability

Types of PSUs (Form Factor)

You may learn essential details about a power supply, such as its size and functions, by looking at its type or form factor. By being aware of these typical form factors, you may pick the power supply you need.

Following these suggestions will help you make sure your power supply fits in your case and functions as effectively as possible:

ATX: ATX power supplies now employ a 24-pin power connector instead of the single 20-pin connection they previously used to power the motherboard (which is still compatible with older 20-pin motherboards)…

A 3.3V extra rail is also included in the ATX power supply. One ATX feature that permits specific software to shut off the power supply is soft-off.

ATX12V: Technically, the ATX12V standards outperform normal ATX, yet both power systems have the same physical shape and size. ATX12V power supplies, now the most prevalent form factor, are available in various models that have been updated throughout time. The most recent versions are ATX12V 2.1 and ATX12V 2.2. These models have a 24-pin primary power connection optimized for performance.

SFF (Small Form Factor): Several small power supplies have been created for compact designs throughout the years. These power supplies are smaller than the usual ATX but still performing well, making them ideal for economic setups prioritizing desk space…

SFF power supplies include the CFX12V (Compact Form Factor), LFX12V (Low Profile Form Factor), and TFX12V (Tower Form Factor) (Thin Form Factor).

EPS12V: EPS12V power supplies include an 8-pin CPU power connection and the 4-pin typical ATX12V units, making them more reliable in server environments. EPS12V form factor power supplies are incompatible with most standard home PC components.


Many people complain about fan noise. A power supply begins to heat up when it generates actual watts. The PSU’s fan speed will rise significantly in response to excessive heat, and it may become quite noisy.

By paying attention to things like efficiency and wattage constraints, you may select a PSU that will power your system without making a leaf-blower-like noise.

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The next thing you need to consider is your choice of the kind of cabling after ensuring the form factor is adequate. No doubt, a PSU’s connections are essential to its operation.

The cables connecting your PSU to other computer parts include features that may make cable management more accessible and let you customize your computer.

Three types of power supply cabling are available: pre-installed, semi-modular, and modular. Therefore, before going further into the issue, let’s examine the many power supply forms.

Modular: By enabling customers to connect the fewest number of cords possible for each device, modular power supply saves up space. The modular design allows customization with customized cables and aids in cable management.

Non-modular: Non-modular PSUs are not detachable and come with all required wires. These devices may be easier to construct but often fill the casing with excess connections and cords.

Semi-modular: Semi-modular power supplies combine the designs mentioned above; they come with some cables attached, but there is space for the client to add more as necessary. It differs from the other two categories for just this one reason.

Because of the pre-assembled nature of non-modular PSUs, they are the most time-efficient option. On the other hand, the modular power supply needs careful connection by the user, which may be challenging for some.

However, with the proper training and experience, you may efficiently link together various wires, freeing up considerable space. As a result, you may improve heat management by increasing airflow. In summary, these things must be considered while designing a power supply.

Examine your Badge or Certification

When choosing a power supply unit (PSU), performance and certification are essential factors. The amount of energy dissipated under various loads is expressed as a percentage of load efficiency or efficiency.

You may choose the 80 plus certification level as a filter while looking for a power supply. It makes setting up your new PC to function at the same level simple. The most impressive badge is the 80 Plus Titanium since these power supplies provide the best power ratings.

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What exactly is an 80 Plus Rating?

The various 80+ efficiency ratings must be considered when selecting a power supply. Simply the concept is that, the different power supplies, or PSUs, are rated and distinguished using the 80 Plus system based on their efficiency and dependability.

It makes it simple for us to understand a power supply’s adaptability and choose whether or not it’s suitable for us.  A power supply transforms high-voltage AC into low-voltage DC for various components to function effectively.

The power supply’s ability to convert AC power to DC power efficiently is essentially shown by its 80+ rating system. It goes further than that since the power supply is tested under a particular load as part of the 80 Plus rating system.

The power supply must maintain a certain level of efficiency at 10%, 20%, 50%, and 100% load to get one of the 80 Plus badges. For your knowledge, Titanium, the most recent 80 Plus grade, takes power supply efficiency at less than 10% load into account.

It indicates that a suitable power supply will turn at least 80% of the AC power from the wall into DC power; not 100% of the AC power drawn from the wall is converted to DC power.

What Kind of Power a Supplier can Deliver?

It will be one of the most crucial considerations when deciding on an adequate power supply. A desktop with a high-end motherboard, twin GPUs, and a custom pure cooling loop demands a more excellent wattage computer power supply than a straightforward setup.

You must specifically deal with the hardware, which is okay but utilize a PSU wattage calculator or another tool to identify your different components and power requirements.

By doing this, you can determine how many watts you need. In general, it’s preferable to err on the side of excess wattage rather than trying to match your requirements precisely.

 If you think your system will require 500 watts (an average number for a pure gaming setup), a power supply unit (PSU) with 600 or 650 watts may be a good option since it allows for future upgrades and overhead. In other words, chooses a power supply that can provide more power than your computer requires.

How to Choose a Power Supply and Other Considerations?

Power Supply Fan

The fan is one of the most significant components of a power supply unit because it prevents overheating and thermal throttling. There must be some high-quality fans attached to the power supply so that it does not overheat and can continue functioning properly.

If the fans on your older power supply aren’t operating correctly, you’ll need to select a high-quality, reliable brand with bearings that can be changed with the ones on the power supply.


When looking for a power supply, you’ll come across terms like “OVP” and “OCP” from various manufacturers. To help you understand your next PSU purchase, it’s critical to understand what they are and what they do. Here is a list of factors that most contemporary power supplies take into account:

OCP: Over Current Protection – Prevents the PSU from drawing too much current. It is programmed to cut power when it senses 130% to 150% greater current. More efficient in multi-rail units.

(OVP/UVP):  Under/Over Voltage Protection – Shuts off the equipment when the voltage reaches a certain level. Most power supplies have 110% to 130% capacity.

OPP: Over Power Protection safeguards against harm if the power supply draws more power than its max power wattage.

SCP: Short Circuit Protection – Disconnects the power supply if the output rail is shorted. Prevents burning and harm. However, the resistance to detect a short circuit must be greater than a specific level. To put it simply, it cannot identify every current fault.

OTP: Over Temperature Protection- This feature shuts off the power supply unit if the operating temperature reaches a particular level. Temperatures greater than specified might indicate overloaded or cooling fan failure, and OTP aids in harm reduction.

BOP: Brown Out Protection – Prevents harm caused by a 10% or more significant decrease in input voltage. Sudden voltage decreases may be problematic since the power supply will attempt to maintain the rated current for as long as possible.

Also, check out our separate post on AMD vs NVIDIA | Which GPU is Better?


It is critical to avoid no-name power supply suppliers and only choose renowned manufacturers. Here is a short list of firms noted for producing high-quality power supplies: Cooler Master, Silverstone, Thermaltake, and Be Quiet! EVGA, Corsair, Seasonic, and Antec are among the manufacturers.

Of course, this is not an entire list, and it is essential to remember that not every power supply manufacturer is a standard unit. As a result, once you have a wattage rating, you must do your homework and study what quality units are available in your pricing range.


A power supply is worthless unless it can connect to and power all of the components in your computer. It indicates that it requires all of the necessary connection types. As a result, you should think about inspecting all of the appropriate connections. The primary connection that powers the motherboard is the first to be considered.

This connection is available in two sizes: 20-pin and 24-pin. The latter is becoming more prevalent, and your power supply will likely give both choices. Just double-check to be sure. Following that is the CPU power connection, which is available in 4-pin and 8-pin configurations.

Many recent motherboards, like the primary power connection, have moved to a bigger size. Check that your power source is compatible once again. The 4-pin Molex connection is the most often used power connector.

Many components, including older HDDs, optical drives, fans, and specific other devices, utilize it. Newer SATA components have their own SATA power connection, but if you run out, you can use a Molex to SATA adaptor.

Power Supply Unit Safety

A power supply in your computer is unlike any of its other components. If you fail to handle it correctly, you risk hurting either yourself or your computer’s hardware. There are two components to safety: the safety measures built into the product by the manufacturer and the precautions you should take to protect yourself.


The most crucial component of the computer system is the power supply since it transforms AC power into DC to enable the correct operation of the PC components.

People must get a high-quality power supply since a low-cost, non-branded power supply might seriously harm your computer’s components. Undoubtedly, the present state of the electronics industry is pretty complicated, given the number of companies and PSU products available.

However, several variables might assist you in finding a source that is right for you. These are the key themes of this article. I’ve covered several procedures and criteria that are important to consider how to choose a power supply.

To ensure that there are no compatibility issues, you must first research the physical aspects of the power supply, such as its form factors, connections, and cabling. When you get a new power supply, I hope this article will be helpful to you, and you’ll always appreciate its features.

FAQs for how to choose a Power Supply

How do I know what power supply I need?

The best power supply for your PC build is one that gives all of the components the right amount of wattage at the same time.
To figure this out by hand, you need to multiply the total amps of all the parts by the total voltage of all the parts. The number you get is the total number of watts your PC build needs.

How many watts should my power supply be?

But a 750W power supply is enough for most single GPU configurations, even with several hard drives and a good Intel or AMD CPU. Most of the time, we recommend 1000W or more for systems with more than one GPU.
If you aren’t sure which PSU is best for your setup, you can use an online PSU calculator.

How do I choose a power supply for my CPU?

Your power supply unit will generate less heat and use less electricity in proportion to how efficient it is. Having said that, a higher level of efficiency typically results in a higher level of cost, so you’ll want to strike a balance that’s appropriate for you.

What are the 3 types of power supply?

Linear power supplies, switching power supplies, and battery-based power supplies are the three subsets of regulated power supplies.
The linear power supply is the least complicated of the three fundamental designs for regulated power supplies; yet, both switched power and battery power have some distinct advantages.

What are the 5 factors to consider when selecting a power supply?

You need to examine the form factor, the efficiency, the amperage, the protection, and the cables that you will require, in addition to any other characteristics that you are searching for.
Investing some time and effort into making an informed decision will save you money in the long run and ensure that your personal computer operates as effectively as possible.