When I was looking at some motherboards I saw some of the more expensive ones marketed as have 'digital power delivery'. This confuses me, do they not all use PWM controlled buck regulators, which IMO makes them digital. Is this just marketing gumpf for a voltage controller that has an I2C bus on it that talks to the bios?

Or do the buck converters on the cheaper motherboards still use some old form of analog oscillation? I'd find this very hard to believe given that we should be looking at at least 90% efficiency at most loads or cheap motherboards would regularly self immolate.

Cheers!