One of the most difficult components for first-time builders to choose is their power supply. Power supplies won’t improve your framerate and they aren’t really a big part of your system’s aesthetics. However, there is no component more central to your system’s long-term health than your power supply.
If you choose a low-quality power supply, your build will either not run, or it will suffer over the long term. On the other hand, if you don’t understand how much power you need in order to efficiently power your system, you could end up allocating more of your budget towards your power supply than is necessary and, as a result, lose out on actual system performance.
Important key point before buying a PSU (Power Supply Unit):
Form Factor
Wattage of PSU
Power Efficiency
Modularity and cables
Premium Power Supply
Form Factor
The next consideration is a simple one – you’ll need to pick a form factor that you’re sure will physically fit into your case. Fortunately, there are standards in terms of power supplies just as there are in cases and motherboards.
This topic can get quite complicated, but the important thing to remember is you’ll want to match your power supply with your case and motherboard. The following is a basic overview of the most important power supply form factors today.
ATX
ATX12v
EPS12V, SFX12V, and Others
One consideration when it comes to PSU form factor is the physical size of the unit. For the vast majority of desktop PC users, standard ATX power supplies should be fine. If you’re a small form factor PC (SFF) enthusiast, you’ll want to do a little more research to make sure your PSU will fit. There is a wide variety of SFF PSU sizes, like SFX, CFX, and more, so make sure you find the PSU that works with your case, no matter how small your PC.
Wattage of PSU
When selecting a new PSU, one of the most common questions asked is, “How many watts is enough?” As is often the case in the world of PC hardware, the answer varies widely depending on the unique needs of your system.
Generally, more complex systems require more power to run. A desktop with a custom liquid cooling loop, a high-end motherboard, and dual GPUs is going to need a higher wattage computer power supply than a simpler system.
It’s impossible to give an exact recommendation without knowing specifically what hardware you’re working with, but using a PSU Wattage Calculator, or determining the power draw of your different internal components and adding that together, can give insight into how many watts you need and Always make sure the PSU you purchase has sufficiently high continuous power output, and don’t choose solely by peak power capabilities.
Power Efficiency
Wattage is certainly an important consideration when choosing a desktop power supply, but so is PSU efficiency. Inefficient delivery leads to wasted power and more heat, which can potentially decrease the lifespan of your components.
Because this is such an important consideration, there’s a relatively straightforward independent rating system in place. You might have noticed the “80 Plus” rating on many power supplies, often listed alongside a precious metal. To receive this rating, a power supply must be at least 80 percent efficient, meaning that a maximum of 20 percent of power is lost as heat.
The more efficient your PSU, the less power it uses, and the less heat it generates. That said, higher efficiency usually means a higher price, so you’ll want to find the balance that works for you. Even the most efficient PSU will still generate heat, however, and most use fans to disperse that heat. Many power supplies are designed so that the fan will only turn on when it needs to — that is, when the PSU hits a certain threshold. Features like this help to reduce noise.
Modularity and cables
Another important distinction when it comes to the physical attributes of your PSU is whether it’s modular, semi-modular or non-modular.
A power supply operates by converting energy from a wall socket and routing that power to each of the individual components in your system through a variety of cables. If your power supply is non-modular, these cables will already be soldered to the circuit board, meaning you don’t get to choose the cables that will be in your build. All the cabling, even the ones that you don’t use, will need to be stored in your case.
Modular power supplies, on the other hand, don’t come with the cables attached. This changes the installation process, as you’ll need to connect each cable to the PSU and the component that it is powering, but that also means you can optimize for fewer cables. This results in a cleaner build and potentially better airflow. Most people aren’t going to use every connector provided by the average power supply, which makes modular units a little more practical, as well.
There’s also a third, in-between option, creatively called a semi-modular power supply. These are exactly what they sound like: Some of the most frequently used cables are attached to the PSU, while some you’ll have to connect yourself.
Premium Power Supply
PC building is all about customization, and power supplies are no exception. In addition to everything we’ve discussed, there are a huge selection of additional features you can get from premium power supplies. Features like RGB lighting, additional connections, OLED Power Display to show Real-time power uses, testing buttons and power draw measurements via internal USB connections are luxuries more than necessities, but they are options if you’re interested.
An interesting aftermarket enhancement to consider is custom power supply cable sleeving. These custom cables allow the user to decide the color and material of their power cables, which adds a further level of customization to your build. This is purely aesthetic, but it’s another way to add some flair to a sometimes-overlooked component.