First of all, you should know that actually 12VO in a sense is not really new. Companies like Dell, HP and Lenovo (especially HP) have long used power supplies that only have a + 12V rail, although obviously in these PCs the motherboards are equipped with all the necessary components (basically DC / DC converters) to be able to convert the voltages. However, even though this has been around for a long time, it had not been standardized until now and was often used with specific (ie non-standard) connectors on the power supply.
What is the Intel ATX12VO standard?
Let’s start with some background: Intel published the original ATX (not -12VO) specification for motherboards and power supplies in 1995, and the current ATX12V (not -O) specification in 2000, from which we can draw two important conclusions. to get started. First, ATX12VO is an overhaul of Intel’s own technology rather than the company trying to take the reins out of thin air.
Second, the ATX12V specification is old; technically ATX refers to the form factor and overall design (currently at version 2.2) and ATX12V specifically refers to power supply characteristics (currently at version 2.52). Note that the ATX12V specification is also responsible for things like the 120mV maximum ripple requirement, which highlights its age.
The power supplies provide voltages of 12V, 5V and 3.3V to the motherboards, divided into three different rails. Of the cables that come with modern power supplies, there are 5V and 3.3V pins only on the ATX 24-pin, MOLEX 4-pin and SATA connector; PCIe, ATX12V and EPS12V connectors use only 12V and ground.
One of the reasons for this specification is that according to Intel, 3.3V and 5V power is used much less in modern PCs than when the ATX specification was published decades ago, and less and less is used (the reality is that yes it is used a lot, but according to them only in peripherals and some storage media, as if this were not enough).
With all this in mind, Intel has published this specification that they call “12 volts only” (12 volts only, 12VO), which uses a single 10-pin connector to replace the 24-pin ATX connector and, as the name suggests, the source will become a mere 12V transformer through all cables, leaving the motherboard to do the rest of the work.
The specification includes a complete set of electrical and physical guidelines for building Intel ATX12VO-compliant power supplies, including CFX, LFX, SFX, TFX, and Flex ATX versions, as well as recommendations for connectors and cables.
What is the rationale behind the ATX12VO standard?
The difference today is that Intel is moving to standardize this ATX12VO and the main reason is to more easily meet the efficiency requirements that government organizations are implementing for devices such as power supplies. These regulations apply to pre-built systems and not to power supplies that we can buy separately, yes.
In other words, removing the 3.3 and 5V rails from the power supplies literally removes two DC / DC converters, leaving a single AC / DC transformer for 12V and thus avoiding power losses in these conversions, so the efficiency of the power supplies will be much better.
Now what they’re really doing is move the problem elsewhere because the hardware devices still need the 3.3 and 5 volt rails to work and so now that transformation stage is carried over to the board and the energy efficiency will degrade there instead of at the power supply. This standard is, therefore, a mere “patch” to comply with the legislation but that only serves to make things worse, since the transformers that will integrate the boards will be worse and more inefficient than those of the sources themselves.
What are its advantages and disadvantages? How will modern PCs change?
We are going to start by listing the advantages that this standard would have compared to the current one, which are mainly two:
- The design of the power supply is simplified, lowering its cost and making it much easier for manufacturers to achieve high levels of energy efficiency, required by regulatory bodies.
- The size and number of pins of the main motherboard connector is reduced from 24 to 10 pins.
And now, let’s talk about the downsides:
- Intel ATX12VO makes the connector smaller but does not eliminate the DC / DC conversion stage for the 5V and 3.3V rails, still necessary for SATA and USB devices for example. This, although it lowers the cost of the sources and makes them more efficient, makes motherboards more expensive, will make them more expensive and also will worsen the efficiency by separating both the DC / DC transformers.
- Although the size of the main connector is reduced, the EPS 4 + 4-pin connector is still required, as well as the rest of the source cables.
As you can see, this standard is simply a patch to be able to comply with the energy regulations that government agencies are requiring and nothing else, but all it does is pass the problem of the power supply to the motherboard. In addition to this, and taking into account that these regulations will only affect OEM PCs, this means that in all probability we will not see changes in the conventional consumer market, that is, in the power supplies that we can buy in stores, as well as on the motherboards.
Intel ATX12VO is therefore not a standard that we will see “standardized” as such, but will simply affect the OEM equipment of the main manufacturers, which will now be less efficient and will give more problems than before. But normal PC users can rest assured that there will be no change, at least not in the short or medium term (we will see what happens when the “thinking minds” who have had these brilliant ideas realize that now the inefficient will be the motherboards and decide to attack these as well).