By Jonny Gerow posted Mar 13th 2013
So how does a better PSU equate to a better computing experience? Consider this: If your power supply isn't doing a good job of regulating voltage and filtering ripple, what is?
The computer power supply essentially converts AC to DC. Older or more basic computer power supplies convert AC to multiple DC voltages (+12V, +5V, +3.3V) at the same time. Newer, more advanced power supplies, convert AC to +12VDC, while smaller DC to DC power supplies within the power supply's housing convert the +12V to lesser used +3.3V and +5V. The latter is more efficient because lesser used voltages are not converted unless they're required and converting DC to DC itself is more efficient than converting AC to DC as it requires fewer and smaller components.
After that voltage is converted, it's filtered with inductors and capacitors.