Btw, some of my miners run at 2400 rpm while I set them to %30 and some run at 2280. Does anyone happen to know why.
1) one set of chips could be better then the other
2) the heat sink may be pasted better
3) the firmware may be different
4) there are different pcb boards you could have two different boards.
5) one psu gives better power then the other thus affecting the temps thus causing the fan to spin faster
6) something else that I did not think of.
Plus I've also found that moving them around or one place form another place can do it the list can on as to why and there might not be a thing wrong either .