drivethrowinguy

About ~3/4 of the power a drive uses goes into the spindle motor. Only a relatively small part of that is dissipated in the bearings (a quarter or so), all the rest is gas-platter friction, turbulences due to the heads etc.

Fun-fact aside: The head fly height in helium drives is ~1 nm.

You're probably confusing these with SMR drives. These here are standard PMR, so they are just like any other hard drive regarding random I/O.

Are you sure that you had Seagate EC drives, and not Seagate Archive drives? The latter are DM-SMR and therefore poorly suited to pretty much anything doing random write I/O (e.g. rsyncing directory trees, rdiff-backup and so on). However, with the correct workload (object store, log-oriented storage) they perform admirably, especially for their price.

With DM-SMR strange noises and paranormal drive activity has to be expected since the drive can spend considerable time flushing it's PMR buffer (~16 GiB) to the shingled zones.