i received my Z9 mini 3 days ago, overclocked it to 743 about 5 hours ago, fan 100% (i dont care about the noise), temp of the cells is 58 celcius
so far i have an average of around 17 KH/s with peaks at up to 25KH/S
edit: also without overlocking it was around 11 KH/S, so it was pretty good even though it was running at 500
At aoutomatic fan speed it will let it go to about 70 degrees celsius and try to keep it there as max.
at 80 degrees it restarts.
Soo..
You probably don't need to keep it at 58 degrees.
Every degree will cost som fan speed?
try to find a sweetspot where it runs stable and save the fan a little.
Just my thoughts !!!