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How Intel's ATX12VO Power Supply Specification Will Change the Future

A significant change will alarm the balance of power in the world of PC power supplies for the first time in 20 years




We don’t write about power supplies very often, but Intel’s new ATX12VO specifications (the letter O at the end, not zero) will soon be implemented in ready-made power supplies from OEMs and system integrators, and this is a significant change in design power supply units (PSU).

The ATX12VO specification removes voltage limits for PSUs to improve PC performance standards and meet strict government regulations. But although the specification, in fact, removes voltage from +3.3 V, +5 V, -12 V and +5 V from the power supply in standby mode, these voltages will not disappear anywhere - they simply go to the motherboard. This is another big change, so keep reading to find out more.

Do not take my ATX12V PSU from me!


No panic, dear homemade products: food police agents will not rush to your home, and your favorite 1500W ATX power supply will not be taken away. ATX12VO is now targeting OEM PCs, some of which have already embarked on this path.

ATX12VO will not replace ATX12V for those who assemble their computers themselves. “Intel plans to continue to publish specifications for the ATX Multi Rail in order to maintain compatibility with existing motherboards and PSUs so that OEMs and consumers have as many choices as possible,” Intel representatives told PCWorld.


From 2006 to 2016, the voltages gradually go from 3.3 V and 5.5 V to 12 V.
Left: 600 W power supply in 2006. Voltages 3.3 V and 5.5 V were used in 25% of cases.
Right: 600W PSU for 2016. Voltages 3.3 V and 5.5 V were used in 15% of cases.

3,3 5 ?


Nevertheless, the rejection of mandatory supply voltages of 3.3 V and 5 V, or, as they called it, “lines” [rails], in a power supply unit is a serious change. PCs initially worked mainly on 5 V, but over time they switched almost completely to 12 V. One manufacturer of PCs in the region of 2006 produced 600 W PSUs, in which 25% of the power provided 3.3 V and 5 V. And after ten For years, a similar 600-W PSU from the same company devoted 15% of the power to these voltages.

The efficiency of the PSU (which part of the power the PSU converts from AC in the outlet to DC for the PC) has also evolved. In 2006, BP operated with an efficiency of 78%, and in 2016 with 98%. This means that in 2006 the power supply units had to take 127 watts from the outlet to give out 99 watts, and in 2016 - to take only 100 watts with the same result.

Since the ATX12VO refused 3.3V and 5V power buses, the large 24-pin connector will decrease significantly - to 10-pin Main Power, and will become similar to what we already saw this year with Intel Compute Element .



It's all about efficiency


Performance gains are the main reason for promoting the ATX12VO. “Desktop computers are constantly increasing their efficiency, and the loss of converting AC to DC becomes the largest consumable item in times of downtime,” Intel told PCWorld. “Existing ATX PSUs with different voltages (5 V, 3.3 V, 12 V, -12 V, 5 V standby current) do not work effectively at low loads in modern computers in idle mode.” Since such a PSU sends very small currents along all voltage lines, its efficiency is at the level of 50-60%.

The new ATX12VO specifications significantly improve this performance. “By switching to a single voltage,” Intel explains, “it’s possible to minimize conversion losses and achieve 75% efficiency with the same downloads.”

And although increasing efficiency means that less energy will be used and less money will go to the energy company, PC makers do not take action on their own. They have to comply with increasingly stringent rules restricting PC energy consumption - in particular, the requirement of the California authorities, which comes into force in July 2021. “Recent government decrees regarding energy require OEMs to drastically lower their PC’s power consumption in idle mode,” Intel explained.

You might think that the California Energy Commission would concentrate on the power consumption of desktop computers under load, but regulators really concentrate on increasing efficiency in idle or in sleep mode - in their opinion, this will be most valuable for saving energy. It is assumed that desktop computers are idle much more often than they are loaded.



Manufacturers say it is very difficult to meet the increasingly stringent requirements for idle power consumption when the power supplies deliver 3.3 V and 5 V, so the new ATX12VO specifications will transfer support for these voltages to the motherboards.

How ATX12VO can reduce the cost of power supply


ATX12VO brings change, and change can be scary, but not so bad. One PSU manufacturer told PCWorld that switching to the ATX12VO standard should “dramatically” reduce the cost of PSU assembly. John Gerow, Director of Research and Development at Corsair BP manufacturer, agrees that costs should decrease and efficiency should increase.

However, these tensions will not disappear, they are still in demand. “5B is still widely used,” explained Herow. - It powers SSD, USB ports and RGB backlight. And although 3.3V is no longer used so widely, according to Herow, Corsair still use this voltage to power the LEDs of their AIO coolers.

These stresses move. This will not be a small board in the PSU - 3.3 V and 5 V will be integrated into the motherboard.

There are pros and cons to this change. Herow believes that it will provide more opportunities for fine tuning the PSU for specific purposes. “You can scale +3.3 V and +5 V exactly for what is needed in this assembly, and nothing more,” Herow said. On the other hand, new functions are added to the motherboard, which increases its cost and requires scarce space on the motherboard. And, of course, these schemes will have to be cooled, which is why the importance of ventilation is growing.

At PCWorld, Herow was asked who has higher energy efficiency, a PSU or a motherboard. Herow said that everything is ambiguous here. “Motherboards have to do this on a smaller scale, so these small loads are easier to regulate with the help of small components,” he explained. However, as everyone knows, motherboards are gentle creatures. “These small components are more susceptible to damage due to“ incorrect voltages, ”said Herow,“ so the PSU and motherboard should really work in the same team. ”

What motherboard manufacturers think


Motherboard manufacturers surveyed by PCWorld magazine were mostly optimistic about the ATX12VO. One told the magazine that such a transition would make it easier for motherboards to manage power when the computer boots, which may cause problems when using non-standard power supplies. If the motherboard manages all three voltages, it will be able to better monitor and calculate power consumption and reduce the risk of abnormal power surges from the PSU.

Also, the manufacturers surveyed believe that local control of 5 V and 3.3 V can be more dynamic, which could potentially benefit power-sensitive devices such as USB and audio controllers. Also, in their opinion, such a situation will help to improve protection against excessive current and voltage.

However, according to our sources, transferring voltage and power connectors to the motherboard will mean an increase in load in the form of additional components, an increase in the size of the MA and the number of layers in the board, which means that they will increase complexity and cost. Also, if it is necessary to use very powerful consumers - for example, 1,500 W - heat dissipation begins to pose a problem.

Another manufacturer said that the ATX12VO seemed “interesting” to him, and that he could improve the internal aesthetics of the systems. Today's power connectors for the ATX12V are thick, clumsy cables. ATX12VO will make the connector smaller and the cable thinner, so it will be easier to handle.

One manufacturer noted that it will complicate the issue of reducing noise from the board, not to mention performance issues. As a result, the first motherboard with support for ATX12VO will most likely be expensive, but prices will fall with an increase in output volumes.


Intel's new specification uses a 10-pin connector versus the regular 24-pin that is used on most prefabricated desktop computers today

Not for enthusiasts yet


The ATX12VO specifications first appeared in July 2019, but there is no clear schedule for their implementation yet. Intel says hardware commissioning is entirely up to OEMs and when they are ready.

Most specs are not for enthusiasts, at least not yet. First, consumers usually start to worry when they are required to buy a new motherboard. Secondly, supply and demand play a game that one manufacturer called "weakling." PSU manufacturers do not want to release ATX12VO specification products for computer enthusiasts, as long as there are no ATX12VO motherboards. Motherboard manufacturers do not want to create products until they are supported by PSU manufacturers.


, ATX12VO – Mini-ITX, . , , 3,3 5 , SATA.

ATX12VO?


It is still unknown how the motherboard with support for ATX12VO will look, or how much they will cost. The motherboard itself will most likely be a bit fatter, since 3.3 V and 5 V control modules will appear on it. Judging by the specifications and manufacturer reviews, the future of motherboards with ATX12VO support will most likely not differ much from the existing ones.

The ATX12VO’s main power connector will be much smaller, and the cable will be much more flexible. If the board has enough energy from one connector, it may not even require you to connect an additional 8-pin power supply. The specification allows you to supply 12 V via the EPS12V connector.

One of the problems may be connecting drives powered via SATA - such as hard drives or 2.5 "SSDs. Today they are included directly in the PSU. On motherboards with support for ATX12VO, you will need to include a power cable in the motherboard, and then - The specifications allow you to place up to six power connectors, but their number will be determined by the manufacturer.The same SATA connectors will be used to power the drives, as well as for the AIO / CLC cooler or LED backlight.

If you want to connect the good old Molex connector, the new specifications allow PSU manufacturers to offer this option directly, but, of course, only with a voltage of 12 V. If you decide to connect a very old device with Molex and 5 V, you will have to connect to the motherboard boards using the SATA-to-Molex adapter.

But for fans to build their own computer, the situation will not change much. The whole question is how it will work out with new motherboards and PSUs.


The power supply of the GPU in the tower case of the Apple Mac Pro goes through the motherboard. The ATX12VO will have a similar system - but only for SATA power connectors

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