I think i read in this thread some place how it is better to use a 220 line over a 110 line that's the truth i just tested that to find out on my 110 line if the meter is right It uses 4.8 amp or 562 watts at the wall with 4 amd cards and CM8 i plugged it into a 220 line it dropped off a AMP or so ,right now i have no real way of proving it other then what the PDU shows in amps used on the 220 line from what the 110 line meter shows. I'm using a Vga 1300 gold and looking at using SIdehacks break outboards with 1500 watt pat server psu's on a 220 line. there cheaper.
Using Server PSU's Might be better the way ?.
yes 220v line is better than 110v for mining
here is a simple formula
power = current x volts
1000watts = 4.5454 amps x 220 volts
1000watts = 9.0909 amps x 110 volts
higher voltage is the secret ingredient to transfer electricity to hundreds of miles from the power plant by using hundreds of thousand volts, higher voltage is higher efficiency by having more watts for the wire.
regarding using server psu, i think it is better to use server psu because it is designed to work 24/7, typically they are rated in "platinum" and second hand server psu tends to be a lot cheaper. the only problem i see with second hand server psu's is if you get a unit that has been used for a very long period of time, no matter how great their build, they aren't designed to last forever plus they don't have warranty from the manufacturer anymore. (some server PSU's are very noisy btw )
using typical PC PSU has an advantage too because typically they are bought brand new, and good PSU's can have 5 year, 7 year and i think there are some with 10 year warranty..the only disadvantage is the price.
Another problem with the server PSU is that you need some special adaptor to use it. They do not have low voltage output.