Does PR4100 have loud fan? Does Intel CPU have AES-NI?

Is it louder than EX2 Ultra?
Is it ok to disconnect fan?
Does it have hardware encryption?

My experience is the fan is only “loud” when cold booting. It settles back to almost inaudible when the unit is up & running.
Personally, I wouldn’t advise disconnecting the fan. Its there for a reason and also the system may detect a fan failure (disconnection) and cause you other issues!
Can’t help on encryption - Have a read if this thread:

thanks for insight, after pondering pros and cons i will go probably with fanless mini pc running windows server and connect bitlocker encrypted hardrives via usb or sata.
quiet, secure and much cheaper but no cloud access.
wished they sold os5 for windows server