Just like the Ultrastar 18TB, these are 9 platter drives. WD was able to increase the data storage on 9 platters to 20TB without resorting to SMR, but rather with using optiNAND to store part data.
iNAND is used to store the data about the data (metadata), and the disks are used to store the actual data. The result is a CMR 20TB drive with 2.2TB per platter.
Other than that, they are the same as other Ultastar drives - helium sealed to reduce drag (all 12TB+ drives are currently helium sealed), 3.5" form factor, available in SATA and SAS, 5-year limited warranty, 2.5M hours MTBF, etc.
As with all large capacity hard drives, transfer speeds do not keep pace with increased capacity. This drive is not an exception - it has the same transfer speed as the 18TB drive.
We have these drives in stock now.
