Hi, looking for something efficient to power this board with besides an over-spec'd inefficient PC PSU, and I'm wondering if the 3.3v rail from the ATX connector is actually used at all or if this board regulates its own 3.3v from the 5v or 12v rails? I see Mean Well have a nicely sized psu that provides 12v and 5v that should be suitable provided the board is regulating its own 3.3v. Thanks