one thing I noticed is that if the fan is set too low manually on the mini batch 4 the machine will cut speed back accordingly. So if the controller sets the fan to say 4500rpm and you drop it too low the speed will reduce. The batch 4 mini's need a fan simulator and other hw mod to fan to run batch 1 firmware unless you don't mind the fan running 100%
What do you mean "cut speed back accordingly"? Are you saying the frequency and hashrate drops?
Otherwise, I would not expect a "fan simulator" to not act any different than a regular fan in the condition you have described.
Another point on the "batch 4 minis" is that I believe their availability is only mainland china?
-j