Motherboard Power Phase

A motherboard has to draw some power from the computer’s main power supply to work. However, the system is more complex than connecting plugs directly to the power source. Motherboards have different power specifications and requirements, and you must know them when picking a new one for your desktop PC. Keep reading to learn more about motherboard power phases!

Computers differ in their power needs, mainly because of the chipsets and their power demand. The motherboard has to provide for the demand. Otherwise, the system becomes inefficient over time. Below, we’ll show you some of the existing motherboard power specifications you must know. We’ll also talk about their functions, strengths, and limitations.

What’s a Motherboard Power Source?

As mentioned earlier, the motherboard needs electricity from the main power supply to work. In addition, it requires a special connection to enable effective performance and prevent damage. These connections have their protocols and standards, and using them wrongly can damage the PC irreparably.

The power source converts the AC current from the primary electric source to DC current that the computer can safely use. Typically, the power source can pass 110 to 220 volts into the motherboard, where the computer uses the power in continuous voltage streams (in 3.3V, 5V, +12V, and -12V alternating cycles).

It’s important to note that power input specifications differ between countries worldwide. Therefore, the 110-220V range is only an intermediate representation.

Power Supply Design Types

Power supply models have different designs to fit into various motherboard and PC sizes. Here are some common design types we have:

Linear Power Supply

The linear power supply design works by taking the 110-220V power input from the primary power grid and lowering its value for the computer to use safely. The power input is still in its AC form, and as such, the power supply model has to filter and modify through sets of diodes to convert to a safer and more usable format.

Linear power supplies are suitable for electronic devices like cordless phones and low-power computers.

Switching-Mode Power Supply

One of the main limitations of a linear power supply is that its physical size increases when more power is necessary. That’s because the transformer has to get bigger the moment the frequency of the input AC voltage becomes higher.

This drawback means that modern PCs and motherboards can get unnecessarily big for their output. Therefore, there was the need to consider a smaller and more efficient option.

The switching mode power supply design came to solve the issue. The newer design increases the input AC voltage value before passing it through the transformer. That allows the electrolytic capacitors to remain small yet powerful.

You can find switching mode power supply (SMPS) in modern DVD players and PCs.

Power Supply Form Factors

These days, you can find different power supply standards for motherboards. The standards are known as form factors, and they dictate the physical size of the power supply unit and the connector types. The form factors you can have on your motherboard power phases include:


First on the list is the AT-Series power supply connection for motherboards. Initially introduced by IBM in 1986, the AT was the standard PC power supply form factor until it got replaced in the mid-1990s. It operated on four voltage outputs: +5V, -5V, +12V, -12V.

The AT power supply interfaced with the motherboard using a 12-pin connector. At the time, it could only use peripherals and cables that also had the 12-pin standard.

You can find the connector type in PC, AT, LPX, and XT motherboards. The AT-Series connector features two separate cables (the P8 and P9 cables) that go to the power supply. Each cable has six pins at its tips and is end-to-end.

The AT-Series connector has a clamp on the pins to ensure that you only get to install it in one direction. While this arrangement allows for a secure connection, you must take care to cover the receiving pins on the motherboard with that of the cable. Any gap can see the motherboard getting burned.


The ATX Auxiliary connectors are unofficially an iteration over the AT-Series. They came about due to more power demand from modern motherboard architectures. Also, the connection needed to deliver current at 3.3v, which is the voltage DIMMs (Dual Inline Memory Modules) for chipsets to operate. These voltages are the “Standby Power” for the computer, as they stay on even when the PC is off. This state allows you to turn the computer on or off without the power switch.

If you need a system that can handle power draws of over 250 watts from the power supply, you should check for ATX Auxiliary connectors for your motherboard. Any other connector would virtually melt under such loads. Also, the ATX came with a different 20-pin connector. As such, you can only use 20-pin compliant peripherals and cables with it.

ATX12V 1x

The ATX12V 1x came due to more power demands from modern PCs. It included two additional connectors to the ATX: one is a 4-pin 12V connector, while the other has six pins. Also, some versions of the ATX12V 1x had extra SATA connectors around the time.

ATX12V 2x

The ATX12V 2x was developed due to the emergence of the PCI-Express connectors. It made motherboards do away with the 20-pin connectors for a universal 24-pin one. The ATX12V 2x is one of the more common power supply options on the market today.

Power Supply Importance

The importance of power supplies is immense. Unfortunately, most motherboard shoppers undermine their functions, because it looks like a “set and forget” component for the PC.

For starters, your motherboard power supply is the lifeforce of the entire unit. That means that no matter how powerful and specked-out your chipset and disk storage spaces are, they need a great power supply unit to function correctly.

Also, power supplies can improve the durability of your desktop setup, in the short and long term. They’ll also help you to regulate your electricity consumption since they often have standard power management features as well.

However, it’s still vital that you pick a suitable power supply unit, as a lower quality one can cause hard-to-diagnose PC issues down the road. A defective motherboard power supply unit could also lock up your PC and access to the storage.


It’s crucial to pay attention to the power aspects of your motherboard, as the other components depend on it. They control the amount of electricity going into the board and how well each component would use the power.

You need the proper connectors to avoid damages and failures to both the motherboard and power supply. The AT-Series and ATX Auxiliary connectors mentioned above are the most commonly used components on the market today. It will help to check out if your prebuilt or custom motherboard supports any of them.

Furthermore, you can also find proprietary connections in other systems. Manufacturers may have a specific power situation they’d like to address, and you can check their motherboard power manual to see if that fits your use case.