I don't have the Thunderbay but I do have the Qx2 which is the basis for that model, and it is LOUD! There may be something wrong with my particular unit but the fan is louder than all 4 hard drives combined all by itself. I am sending mine back. I just got a Drobo 5D and it is MUCH quieter! And be aware that the Thunderbay does NOT have a hw RAID controller like the Qx2, but uses software RAID; how they plan for you to use software RAID with 4 disks I don't know. If you're going to spend that much money for a case then I would recommend getting something with a real controller onboard like the Promise Pegasus2 or the Drobo 5D or something else.