@ uncle: i know the general theory (about the sensors), but i don't understand the difference from 15 and 0 movements ...

i try to explain here, for example:

0 movs: seems to be dead (the sensor obviously)
from 1 to 2: the sensors aren't reliable
from 3 to 15: they are reliable, BUT if i've a clocked system my sensors go around 15 (instead if i've a default cpu my sensors go around 3)

what do you think about? TIA