Right. But my question was if the efficiency is constant throughout the loading. E.g., if it's 85% efficient, is it 85% efficient at 20%, 50%, 65%, 100%, etc. loads?
If it is only most efficient at full load (true for a lot of other electronics/motors), then I don't want to buy one larger than my needs as it increases the cost and actually lowers my profitability.
most psu's work best in the 65% load range not the 100% load.
server psu's can work well at higher numbers but they tend to get loud.
Do you want to know a decent server psu ? you need 208 vots to 250 volts
do you want a good atx setup. 2 of these
http://www.ebay.com/itm/Rosewill-Quark-Series-850W-Full-Modular-Gaming-Power-Supply-with-LED-Indicator-/291426924760? 2 of these will do 1 avalon 741 with overhead and good efficiency you would be hard pressed to find a better 120 volt atx for this price of 115+115 = 230
if you have proper voltage of 208 or higher
1 of these
http://www.parallelminer.com/product/94-platinum-1200w-power-supply-kit-for-a4-dominator-litecoin-miners-110-240v/will do 1 avalon 741 it will run loud but it will work.
here is a server kit for 120 volt that will do 1 avalon it is cheaper then the 2 rosewill
http://www.parallelminer.com/product/platinum-94-1500-watt-power-supply-kit-for-2-a4-dominator-litecoin-miners-ltc-litecoin-100-240v/all of the above will work with proper voltage for 1 avalon 741
I have this on hand below needs 208 to 250 volts
it should do 2 avalon 741's I have yet to test it.
http://www.parallelminer.com/product/94-platinum-2400w-power-supply-kit-for-2-a4-dominator-litecoin-miners-200-240v/use code
Slush for 5% off on the servers.