Quote:
Originally posted by Since87
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Whether this hypothetical equally efficient fatter supply can be found I don't know. I haven't done much looking, but most of the supplies seem to be rated around 70% efficient.
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Valid point, though i've seen that higher wattage PSUs tend to have lower efficiency. That's more like 80% for 250W or lower PSUs, 70% for 400W and 65% for 550W. Higher efficiency ratings exist of course, but they come at a price...
Active PFC helps getting the efficiency up, again rising the price.
You say "major losses comes from RI^2" but that's not exact in a switched PSU. Huge losses come from the regulation. Mostly resistive components (resistors obviously, coils) don't produce as much heat as MOSFETs themselves...
All comes down to -> want a cooler PSU, buy a more expensive one (beware of overrated products though..)