If you do not know that answer you don't have full command of mining with the avalon 841

I have complete instructions.

give me 1 minute

this all is for just the A841

https://bitcointalk.org/index.php?topic=3375954.msg37014814#msg37014814

overclocking means loud hot running

underclocking means quiet cooler running.

overclocking  with current prices  means you lose more money  since the gear is not efficient.

under clocking with current prices means you lose less money since the gear is more efficient.

you need a powerful psu to over clock  say 2000 watts
you need  a cold room to over clock

you can have a weaker psu to under clock say 1200-1400 watts  

if your power is lower then 3 cents a kwatt
if your power psu is strong 2000 watts
if your room is cold
if you don't give a shit about noise

Over clock  the gear.

if your power cost is 3 to 7 cents  underclock

if you power cost is 8 cents or more this gear loses money right now.