[hungarianhc]

Forgive me if this is stupid (i know it is, and i think i know the answer...)


The wattage of a power supply doesn't mean it's always pulling that much... right? Like if I build a HTPC with a 500W power supply, and let's just say it's an atom PC using everything integrated (hypothetical - i know not wise), is it still going to pull the standard 20W-ish that an Atom system pulls? Is the wattage just the maximum? THANKS!

 

[MrBobb]

Max.

 

[jim2100]

If you operate a PSU at a small fraction of its rated max power, the efficiency will be lower. For example, an 80+ rated power supply does not have to meet the efficiency number at less than 20% of max rating.


So, while it is certainly true that a 500W PSU will NOT draw 500W of power when given a 20W load, it will probably draw more power than an equivalent 80+ rated 250W or 300W power supply.


But even if the efficiency were absolutely awful, say 50%, you would still only be drawing 40W for a 20W load.

 

[hungarianhc]

Thanks, Jim! Very helpful response!!!