In the retail PC PSU space, most of the focus on new standards and their capabilities in the past couple of years has been on ATX 3.0 and it's quick follow-up successor, ATX 3.1. And while the revised ATX standard is certainly the most important new standard for the rank-and-file PC builder, it's not the only standard that has been released as of late. Intel and its partners have also developed a standard, that in some respects, goes even farther out by dropping some of the legacy aspects of ATX and its increasingly esoteric secondary voltages: ATX12VO.
Short for "ATX 12 Volts Only", ATX12VO is a standard that's been slower to take off as it makes a pretty hard break with backwards compatibility. But with so many motherboard functions running off of 12V (CPUs and GPUs, for a start), the need for a PSU to provide secondary voltages like 3.3V and 5V just aren't what they once were 20 years ago - or even 10. So we've slowly seen PC manufacturers and motherboard makers test the waters, with a handful of designs using the more petite ATX standard.
Meanwhile on the power supply side of things, the outcome has been a bit more interesting, if messy. While ATX12VO motherboards need matching PSUs, there's nothing to say that such a PSU can only be ATX12VO. To reference an ancient meme, the thought at some PSU manufacturers has been "why not both?", leading to high-end PSUs that can bridge the compatibility gap by offering both ATX 3.1 and ATX12VO compatibility.
