I built the rig at the end of January, mining Scrypt on multipools autocoverting to bitcoins, mostly for experimenting. Then changed to X11 in the last period, as profits for Scrypt were going lower and lower.
Checking for example Wafflepool, the BTC/MHs/day of X11 are now about 1/3 of Scrypt, but in X11 I get 4x the hash rate and halve the power consumption, so it's definitely more convenient now, at least for me.
how is that possible, lower power consumption?
I am assuming you are running your cards at full speed.
Different algorithms result in different GPU utilization. Utilization != % Load
Those of us who were around when bitcoin was mined on GPU, already know that different algorithms have different card utilization. SHA-256 always used less power than scrypt, which is relatively memory-intensive. More power consumed, more heat, more noise, etc.
X11/X13 coins take it to the other extreme, and result in very low GPU utilization (approx half of the normal power consumption of the card).
I have 9 GPU on X13 getting about 15 MH/s for 600 watts.