What difference does areal density make?

Hard drive areal density progression has traditionally been measured in terabytes per square inch (TB/in²), but a more intuitive way of measuring it is terabytes per disk (TB/disk), which refers to the amount of data stored on each spinning platter.

Progression in areal density directly impacts how efficiently data can be stored within a physical space. In large infrastructure environments like a data centre where space is at a premium, storage density improvements afford significant efficiency benefits when scaling — a strategy deployed by hyperscale cloud service providers who continually adopt the highest hard drive capacity points available.

It achieves this by offering higher per-platter data density and thus packing in more storage capacity per drive slot, improving data centre utilisation without compromising power and sustainability objectives.

• Higher per-platter density enables greater capacity without expanding physical infrastructure, reducing property costs. 

• Enterprises can improve property ROI for new scale-out or managed fleets with higher per-platter density storage; for example, transitioning from 1 TB to 4 TB per platter allows a drive to achieve up to 44 TB capacity in the same form factor as a 12 TB drive.¹

• Drives with higher areal density, such as Seagate Exos® 40 TB, more than double the power efficiency per terabyte than typical 20 TB Exos drives. 

• Seagate's leadership in areal density supports these scaling benefits for data centres while also lowering the bill of materials (BOM) cost per TB across its full hard drive portfolio, benefiting all markets and applications.