At the beginning of the year there were indications that Intel would introduce the Single Rail Power Supply Desktop Platform Form Factor ATX 12 VO wants to introduce more broadly. It is already used in many complete systems by numerous manufacturers. But such systems are rarely screwed on and so the contacts with this type of power supply are rather few and far between.

We now had the opportunity an ASRock Z 462 Phantom Gaming 4SR with this ATX 12 Take a closer look at the VO connection. With this, Intel beats some partners (including together with ASUS and the Prime Z 490 – S) a path that ATX 12 VO possibly to translate into the masses. Whether and when this change will actually take place cannot currently be foreseen. But let’s first take a look at what ATX 00012 VO at all means:

Currently a power supply unit operates the installed components with 12 V, 5 V and 3.3 V. The 12 – V-rail is now the most important thing for the operation of the system. The operating voltages for the processors, GPUs, memory chips and the many other components are provided by the mainboard and the power and voltage supply on the graphics card. 5 V and 3.3 V are only used by a few components – for example SATA drives and USB devices. But here, too, a change is emerging. In the specifications of SATA 3.2, for example, the supply over 3.3 V is already deleted.

For ATX 12 VO, the 3.3 and 5 V are no longer made available via the power supply unit. The – Pin ATX connector (formerly 19 – Pin) on only 10 Pins together. Depending on the platform, it is supplemented by the familiar EPS connections in order to additionally supply the mainboard or the graphics cards. In the case of the Z 490 Phantom Gaming 4SR from ASRock are 6-pin and 8-pin (EPS). But no matter how many plugs are required here, only the 12 – V-rail operated.

Instead of the power supply, the mainboard will use voltage converters which should provide the additional voltage rails that are still required. 5 V will continue to be required for SATA drives (SSDs and HDDs) and USB hardware is also dependent on 5 V. In the future, this voltage will be offered directly via the mainboard, including the necessary connections, but no longer via the power supply.

On the supply side, there was a High Power HP1-P 650 GD-F 12 S ATX 12 VO available. This is one of the few ATX power supplies that can be connected directly to ATX 12 VO is compatible. The non-modular power supply has an output power on 490 W, an efficiency class is not specified. The main supply via 12 V represents the power supply at maximum 54, 1 A represents what exactly the 650 W corresponds. Further 12 – V consumers are charged with up to 1.5 A, i.e. 18 W, supplied.

The power supply as such offers the ATX on the wiring harness 12 VO 10 – Pin, two 4-pin CPUs, one 8-pin CPU and three 6-pin PCIe. The inside of the power supply is structured much more simply, because of 100 to 240 V only to 12 V must be converted and all other voltage levels are eliminated. Larger circuits and components, which cannot always be optimized for the wide range of the respective application, are eliminated. This ensures a significantly higher efficiency, as we will see later.

A Molex connector is also available, but this also only delivers 12 V and accordingly components such as fans must also be able to accept this voltage. The high-power power supply also offered SATA connections, which according to the 3.2 specification also only 12 Offer V.

The mainboard converts the 12 V into the other voltage rails, as they are just necessary to supply the processor, RAM and other components. But of course other devices also have to be supplied internally that have not yet been covered and these are, for example, SATA hard drives or SSDs. To ensure compatibility, the ATX VO standard adapter shown above. These are set on the mainboard and can supply two or four drives per connection. On the ASRock Z 462 Phantom Gaming 4SR had two of these connections and this will also be the standard configuration, after all, most boards offer six or eight SATA data connections and the corresponding Drives have to be supplied somehow.

Measurement results

For our tests we used the following hardware:

• Intel Core i7 – 10700 K
• ASUS ROG Maximus XII Extreme
• Corsair Vengeance 4x 8 GB DDR4 – 3600 18 – 19 – 19 – 39
• Corsair H 150 i Pro AiO water cooling
• Custom GeForce RTX 2080 Ti

In conjunction with the test system came a Corsair HX 1000 – power supply unit for the ATX standard and the already mentioned High Power HP1-P 650 GD-F 12 S for the ATX 12 VO standard used. We have the power consumption directly at the 00012 – V-rails measured – the voltage recorded by multimeter and the current intensity measured with pliers. The power consumption of the system results from the voltage (U) times the current (I). For the ATX power supply we had to do this in addition to the 12 – V- also include the 5-V and 3.3-V rails n.

Power consumption

Load

224. 6 XX

232.1 XX

W

Less is better

In a first test we tested the two test systems with the Core i7 – 10700 K set under full load using a blender and measure for the ATX system 232, 1 and before the ATX 12 VO system 224, 6 W. Here is the difference so so low that we don’t have it on the ATX 12 VO supply can fix.

Power consumption

Idle

7.4 XX

14. 7 XX

35. 3 XX

W

Less is better

It looks different in idle mode. Here we see a power consumption of in the standard power saving settings , 3 W for the complete system, if ATX mainboard and ATX power supply are used. The ATX comes in the same standard power-saving settings 12 VO system on 14, 7 W – thus consumes less than half.

We can increase or reduce the consumption with all active C-States as well as the Link Power Management for PCI-Express and SATA, which reduces the power consumption via the interfaces when they are not transmitting any data. However, SATA Link Power Management and PCI Express Active State Power Management (ASPM) must also be fully supported by the hardware and software. With these measures we can reduce the power consumption for the entire system to 7.4 W.

ATX 12 VO: A first assessment

ATX 12 VO will play no role for most desktop users for the time being. Instead, OEMs and SIs (System Integrators) will probably rely more on it, because it represents a cost-effective alternative and more and more components in ATX 12 VO are available. This applies to the motherboards in their own design, which sizes such as Dell, HP and many more can indulge in, but also to the power supplies. Manufacturers such as Delta, FSP, Seasonic, Cooler Master, High Power and Channel Well are already working with these OEMs and SIs as well as Intel.

A Z 490 Phantom Gaming 4SR from ASRock and a Prime Z 490 – S from ASUS with the standard desktop functions underline that there are efforts here, which start with the SIs will take effect, but sooner or later they can also be an alternative for every user. Power supply manufacturers such as Corsair already offer adapters for their modular power supplies to ATX 12 VO. Here, however, the advantages of low self-consumption do not arise, since the power supply is still responsible for the other voltage rails.

Specifications from the USA are the driver behind the current development. From July 1st 2021 In comparison to systems manufactured five years ago, desktop systems sold may only be Consume% of the electricity in idle mode. This goes back to a specification of the California Energy Commission (CEC).

The higher efficiency results from the more direct integration of the voltage conversion. In the power supply units, a lot of this is lost in percentage terms in idle mode and accordingly the biggest differences are shown at this point. As soon as there is load on the system, the values ​​for ATX and ATX are the same 12 VO as far as possible.

So the greatest advantage is identified, but how does it look like the disadvantages, if there are any? The power supplies should be less complex, which should theoretically also be reflected in the price. At the moment it is difficult to say whether it will do this, as there is no ATX 12 VO power supplies are available on the market.

On the other hand is increasing the complexity on the mainboards, because the conversion of 12 V to 5 V or 3.3 V must now take place here. However, a mainboard usually does that anyway, because only with 12 V it doesn’t work either and has to provide various voltage levels. But yes, theoretically this creates more complexity and a higher probability of failure due to the mainboard. This only moves from one pocket (power supply) to the other (mainboard). It is currently not possible to estimate whether ATX 11 VO has a negative influence or not with regard to the vulnerability of the hardware.

Even if ATX 12 VO would become more widespread in the coming months: The changes are not that big. The connector is a bit smaller and some hardware would have to be supplied via the mainboard. Without complex SATA and LED supply requirements, this would certainly be doable and not that much of a difference. But it will certainly take a few years before we have ATX 12 VO will also be seen on a larger scale in the DIY environment.