Updated at: 16-03-2023 - By: Leo Hall
Wondering which power supply to buy and why, and what to look out for in particular? If so, you’ve found the proper hub.

Some PC components, like the PSU (power supply unit), have relatively minor features to consider when selecting the best model for your preferences, characteristics that a novice PC builder might be completely oblivious to. And one such feature that power supply units (PSUs) have is modularity.

There are three types of power supply units in terms of modularity: fully modular, semi-modular, and non-modular.

It is the cables themselves that are modular, with both fully and semi-modular units offering varying degrees of adaptability. Non-modular devices, on the other hand, can’t be modified and come with a fixed set of cables.

Consider the advantages and disadvantages of each PSU type beyond the level of user friendliness. Before assembling your own personal computer, it’s important to familiarize yourself with the various components available so you can pick the one that best suits your needs.

PSU Completely Modular Semi-Modular Non-Modular
Cost Expensive Costs a Fair Amount Cheap
In Control of the Cables Excellent Moderate Bad
Airflow Cannot hinder air movement Possible airflow restriction Probably obstructs circulation of air
Efficiency in the Use of Electricity Incredibly efficient in terms of electricity use Greatly conserves power usage. A waste of electricity.
Reusability Possible modular wire recycling for use in fresh installations Some cables could be reused System replacement requires complete removal.
Customizability The possibility of individualized plugs and hues Having fewer cables also means less clutter, but unfortunately you can’t alter the look of the ones that are already attached. No ability to alter cable settings
Size Compact Semi-compact Too many cables clutter the floor.

Full Vs. Semi Vs. Non-Modular: What’s The Difference?

If you know anything about PSUs, you know that it has cables going to various places in your computer. The PSU is responsible for bringing electricity from the wall socket into the computer and regulating the flow of power to the various parts of the system.

Full vs. Semi vs. Non-Modular Power Supplies - Which To Choose? [Guide] - YouTube

Power supplies can be fully modular, semi-modular, or non-modular depending on how much flexibility they offer in terms of connecting cables. For instance, a non-modular power supply unit (PSU) has its cables soldered directly to the device. It is possible to swap out or remove some of these cables in a semi-modular unit. All of the wires and cords in a fully modular system can be easily disconnected and reconnected.

Each type of PSU has its own set of advantages and disadvantages due to its unique construction. For example, non-modular units are the least expensive for PC manufacturers because they require fewer steps in the manufacturing process. On the other hand, the semi-modular and fully modular options allow for greater personalization but come at a higher cost.

In this manual, we’ll delve deeper into the distinctions between these PSUs.

All right, let’s jump right in.

Fully Modular PSUs

All of the cables on a fully modular PSU can be swapped out for new ones without having to disassemble the entire unit. This allows you the most leeway in terms of how you construct things, and it also makes cable management much simpler. A fully modular power supply unit allows you to use only the cables you need, eliminating the need for any of the extra clutter that would otherwise be present.

However, only a subset of PC enthusiasts will be interested in fully modular power supplies. A fully modular power supply unit (PSU) would be excessive in many situations, since most computers only require the cables that a semi-modular PSU typically provides. While the fully modular unit has limited application, there are still some instances where it proves useful.

A fully modular PSU is advantageous because it enables the individual to select the cable colors that best suit their needs. Naturally, this offers an additional layer of customization that a PC enthusiast will want to take advantage of.

Full modular systems allow for the most flexibility in design, but they are also the most expensive. The total cost will be higher than if you were to purchase a modular or semi-modular power supply unit, as you will need to purchase both the PSU unit and any necessary (custom) cables.

Of course, aesthetics and cable management aren’t just about cable color; having a choice in cable length is also important. Cable management is still a strength of semi-modular PSUs, as we’ve mentioned. Nonetheless, only with a fully modular one can you choose the color and length of each cable, while eliminating any unnecessary cables.

Finally, the additional customization options are especially useful with transparent or semi-transparent cases, where presentation is key.

However, we must not overlook the importance of compact cases. A fully modular PSU is a no-brainer for a Mini ITX gaming PC because of the potential for a tangled mess of cables if you aren’t careful during assembly. Lessening the number of cables used would not only simplify the installation process, but also address a common problem with small cases: inadequate ventilation.

How much does it cost?

As previously mentioned, a full-modular PSU is the priciest option, typically costing around $500. Even if you use it nonstop for an entire year, it will last for at least five years. Considering this, the investment is unquestionably justified. Full-modulars use less energy than non-modular PCs, especially if you’ve opted to use a minimal cable setup.

Are there any downsides to a full modular power supply?

The benefits of going fully modular are not universal. Keep in mind that all the cables can be disconnected, which means that some cables could go missing if they were moved. Also, the cables only have a single standard output jack. The model determines the input pin. Any idea what this means?

If you’re in the market for a full-modular PSU cable, do your research to ensure you’re getting one that’s compatible with your specific model. This is crucial because it is not always obvious from the outside how many connection pins are present. The output pins, or the pins used to connect the various components of a computer, are typically standardized. They can now be placed in any convenient location.

Modular vs. Semi-Modular vs. Non-Modular Power Supplies - YouTube

Semi-Modular PSUs

It’s possible to find a happy medium between fully modular and non-modular PSUs with semi-modular designs. The 24-pin connector is always fixed on a semi-modular PSU, and the PCIe and CPU cables may or may not be connected. Modular 8-pin and PCIe connectors are found on some semi-modular units, while others lack them. Those are the only wires that won’t be modular on your semi-modular device.

When comparing modular and non-modular power supplies, semi-modular PSUs provide the optimal balance between flexibility and cost. This reduces the need for the company to produce additional cables because there are already some attached to the device. While this is cheaper than a fully modular unit, it limits your cable management choices.

Semi-modular units, despite their limited adaptability, are still highly desirable. There’s a good chance you’ll need the cables that are built into the PSU, so it’s not like they’re adding much clutter.

While a fully modular unit would allow for customization in terms of cable color and length, these constraints prevent you from doing so. Once again, this isn’t a major priority for the majority of PC manufacturers.

The initial cost disparity between fully modular and semi-modular units is relatively small. However, the cost of a fully modular system can quickly escalate if you need to purchase specialized cables for your system.

However, choosing between a fully modular PSU and a semi-modular one can be challenging if you plan on using the stock cables that come with your PSU. Some customers will decide that it’s worth it to spend the extra money on a fully modular system, while others will decide that a semi-modular system is sufficient for their needs. A person’s own tastes will ultimately determine their decision.

How much does it cost?

In between these two extremes is the semi-modular power supply unit (PSU). The average PC has a lifespan of less than 3 years, and that number can be even lower if the device is prone to overheating. Similarly, its power efficiency is lower than that of a full modular but higher than that of your non-modular system.

Non-Modular PSUs

We’ve already established that non-modular PSUs are exactly what they sound like: power supplies whose cable configuration is fixed. The PSU comes with every cable it could possibly require already attached. This reduces the PSU’s manufacturing cost, but it almost guarantees that you won’t use all of the cables it comes with.

This is obviously a problem with cable management and with the overall look. An excessive amount of unused cables may restrict airflow, reducing the effectiveness of the cooling system. To add insult to injury, if you plan on getting a transparent case, they can be a real eyesore. If the case has built-in cable management features, however, you shouldn’t have too much trouble clearing the desk of excess wires.

Non-modular power supply units (PSUs) are particularly useful for large PCs. Due to their spacious design, these computers leave plenty of room for you to conceal cables. It really is case-specific.

Since larger PC cases are typically more expensive, one way to recoup some of that cost is to purchase a non-modular power supply for your rig and use the extra space it provides for cables.

Finally, non-modular power supply units (PSUs) are a great choice for a novice because all the cables are pre-installed. However, if you’re using a Mini Tower or other small form factor case, you may find the additional cables to be a nuisance.

In addition, as we have seen, a non-modular PSU will be less expensive, making it a viable choice for budget builds, windowless cases, and the pursuit of economy in general.

How much does it cost?

The cheapest power supply unit (PSU) is a non-modular one, typically costing between US$200 and US$300. Due to the inability to control cable routing, the power consumption may be much higher compared to a fully modular power supply unit. If used daily, its lifespan can be anywhere from three years to five years.

Which Should You Choose?

So, how do you decide between these three options? The primary considerations should be (1) your financial situation and (2) how you plan to use the computer. If you want a custom PC but are on a tight budget, a semi-modular system may be your best bet.

This allows for personalization without breaking the bank. In any case, if your finances allow it, you can always switch to a full-modular PSU in the future.

A non-modular PSU could be preferable if the only software you plan on using on your PC are the bare essentials. A non-modular type can be used for low-memory games, documents, and general web browsing.

Can I just change an existing PSU with a new one?

If you’re starting from scratch and building a PC, the aforementioned tips will help. In other words, you’ll be able to put together a great PC out of a collection of parts that you’ve carefully selected. If you’re replacing the PSU in an already-built PC, however, you’ll need to give more thought to a few other factors. Now, take a look at these:

  • Be sure to check the wattage. It’s important to verify that the new PSU can supply enough juice for the computer. One method is to check the wattage capacity of the previous PSU. Use this as a guide when shopping for a replacement power supply unit. It’s possible to ascend, but you must never descend.
  • Power consumption can also be determined by the wattage of individual components, a factor considered by some PC owners. Therefore, you can simply add up the power requirements of the SSD, RAM, Motherboard, and so on to get a total.
  • You should find a computer case that is the correct size for your machine. This is what we call a “form factor” in the industry, and there are many different kinds. The ATX standard is compatible with the standard computer tower. The Micro-ATX and Mini-ATX variants are smaller and typically have a maximum watt capacity of 400.
  • Look carefully at your case and the space you have for the PSU. You can also upgrade to a more powerful PSU by swapping out the smaller case for a larger one.


Any good Modular PSU picks?

Actually, yes! It turns out that Jerry penned a fairly comprehensive guide to the top modular power supplies on the market today.

As a general rule, we try to keep our roundups as current as possible, so the recommendations you find there should still be accessible and able to meet your specific wattage requirements.

What happens if a PSU is too weak for my PC?

The cost savings that would result from purchasing the bare-bones power supply for a computer is a common worry among PC newbies.

While this seems reasonable on paper, you must be careful not to cut corners on the Power Supply or your system could crash or fail catastrophically.

Full vs Semi vs Non-Modular Power Supply - Which To Choose?

How do I choose a PSU that suits my needs, in general?

But what if you just need some reliable advice on where to buy a power supply now? Not a selection of products, but rather a thorough breakdown of what you should know before purchasing a power supply for your computer.

If this describes you, and you’re interested in learning more, I recommend reading Jerry’s Complete Power Supply Guide.


Each power source has its advantages and disadvantages. Any one of the aforementioned PSU varieties can shine or flop depending on the specifics.

Semi-modular PSUs are preferred by experienced PC builders who care about the look of their build and the organization of their cables, while non-modular PSUs are preferred by the average gamer who is more concerned with saving money than with how their system looks.

While fully modular units do have some advantages, most people would be better served by semi-modular ones. Not being able to alter the length or color of individual cables is the only major drawback, but otherwise they are less expensive and have no other significant drawbacks. The market for fully modular PSUs, while modest, does exist and will continue to do so in the foreseeable future.

In terms of adaptability, what kind of power supply do you find most appealing? Do you prefer the ease of non-modular units, or would you rather pay more for the flexibility that comes with modular ones? Leave a comment and let us know.