Hm...
-SkyHawk surveillance drives are designed for always-on workloads of 180TB/year. - So that explains the lower load rating ...
-ATA streaming support
"The Streaming feature set is an optional feature set that allows a host to request delivery of data within an allotted time, placing a priority on the time to transfer the data rather than the integrity of the data. This feature set is defined to satisfy the requirements for AV type applications."
The idea is that for certain applications like recording surveillance video, it's more important to keep up with the flow rate than to have absolutely every byte on the disk be perfect; a bad spot on one frame is OK, but 5 seconds of lost recording while the drive retries the operation is not. The Streaming Command Set enables applications to tell drive that maintaining the transfer rate is the #1 priority; if a sector read returns an error or a read-after-write verification fails (or just can't be completed in time), the drive is to ignore the error and keep transferring the data anyway
Its optional at least... so I assume my FreeNas will not use that option... need to find out how to make sure