Well, I also bought this part and it is unusably loud. I put the hard drives in a Lacie case and it's fine. In addition
one of the hard drives was no longer recognised, so I thought one of them was defective! ...but in the Lacie case there was no problem. Somehow there is something wrong with the software!

I don't know if it's normal. But mine is just as loud and knocks like crazy.

J'UTILISE LE DISQUE COMME UNITE DE BACKUP AVEC RAID. TOUT SEMBLE FONCTIONNER CORRECTEMENT