We have no problems with the 4TB and 8TB hard drives. However, both drives get very warm when they are constantly in operation. That's why I set the hard drives so that they only run when they are accessed and then switch to sleep mode. The 8TB gets 60 degrees warm in continuous operation, the 4TB has a normal 46 degrees. Both of mine stay cool but sometimes take a while to start up when searching for a folder.

Vibrates strongly! Had to put a thick rubber mat underneath. Slow writing speed.