On this subject,
Someone a few pages back wrote this:
if there is no HW errors, disconnects...etc everyone should have 99+% efficiency after few hour (difficulty does NOT matter!)
more hash u have mean less time to balancing out luck/unluck at higher difficulty
but there is no way to be "unlucky" all the time and getting bad efficiency without any reason!
Work Unit = shares / minute @ difficulty 1 (diff1 = 2^16 at scrypt coins)
HRA = average hash rate (kHs)
efficiency = WU * 65536 / 60 / 1000 / HRA
(*100 to get res. as %)
after 1+ week mining i (stil) have more than 99% efficiency on all rig
1h ago restarted my solo card desktop PC = 110% efficiency atm.. and will go down to ~100%
but using that equation (but taking my WU from sgminer) my efficiency comes out at 101.03% for me.
but how can you be more than 100% efficient?