HGST Ultrastar 7K6 & 7K8 Enterprise HDDs
 

This week Western Digital has introduced a new breed of HGST-branded server-class hard drives targeting “mainstream” applications that require 24/7 availability as well as enterprise-grade reliability and performance, but not at a maxed-out capacity. These drives use the latest generation of PMR technology for high areal density, allowing for fewer platters to reduce costs reach their capacity points. Unlike Western Digital’s HDDs with leading-edge capacity, the new Ultrastar 7K6 and Ultrastar 7K8 drives are not filled with helium, and these drives use four and five platters, respectively.

https://www.anandtech.com/show/12366...airfilled-hdds