As you know, in the world of hardware there are exceptions formats and standards, they all have certain characteristics and things. SFX is an electronic format that is about its size, and that they are not based on the ITX mini version instead of ATX but that, electrically, are the same.
What is the SFX voltage?
SFX is a low-power generation housing (SFF, or Small Factor Form), which has a power specification almost identical to ATX and, as a result, as a rule is fully compatible with plugs for these. The only common difference is that SFX format sources (as well as regular mini ITX) do not require – 5V rail (something that doesn't affect when we use modern hardware, since only ISA cards use it and, in fact, it was removed from the ATX 1.3 standard).
The difference is between the SFX and ATX source, as a result size. The standard states that the source in the SFX format should measure 125 x 63.5 x 100 mm (width x height x depth) and follower 60 mm thick at least (so they can be very small), compared to the size of the ATX sources measuring 150 x 86 x 140 mm.
There is a version of the SFX power plant called SFX-L, its size is 125 x 63,5 x 130 mm and its sole purpose is to get a 120 mm fan.
One of the key aspects of this energy use is that, as a general rule (because it depends on each manufacturer), the cables will be shorter (actually, of course) compared to that of the ATX source because, as we mentioned earlier, they are designed for smaller form machines and, as a result, will not require longer strings.
In what situations will you need a font for this format?
You would think that as a general rule, the SFX format source cannot be used on a PC with the "normal" ATX format box, though there are exceptions because many manufacturers include an accessory to be able to insert these sources into the ATX source code, and as we mentioned earlier, some feature long strings. However, this is not normal.
The most common thing would be to use fonts this way where we will add a small PC form factor, with a small ITX board and, most importantly, an ITX mini-box (with cable length). Most ITX mini boxes are designed to accept ATX format sources, but if they did we would have more cable lengths left, which is why this power transmission system works (and for these box manufacturers including the adapter).
