Innovations

What difference does areal density make?

The future of sustainable mass-capacity storage is now.

AI is driving an unprecedented surge in data creation, which is projected to triple by 2028 — far outpacing forecasted storage capacity. 

As a result, areal density innovation is more crucial than ever for sustainable mass-capacity storage.

First, what is areal density?

It’s the amount of data that stored per unit of surface area on a storage device.

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.

Key breakthroughs in the evolution of areal density.

In the era of hard drive innovation, two major recording technology advancements have broken through the assumed limitations of areal density progression — PMR and HAMR.

Transitioning from LMR to PMR.

In the early 2000s, the transition from longitudinal magnetic recording (LMR) to perpendicular magnetic recording (PMR) marked a pivotal increase in areal density.

By reorienting data bits from a horizontal to a vertical alignment, PMR reduced magnetic interference between bits to increase data stability and density. 

Transition from PMR to HAMR.

Because PMR technology hit its limit of areal density per platter at 3 TB, a new way to increase areal density was needed. Developed by Seagate engineers and launched in January 2024, the Mozaic 3+ platform marks the world’s first implementation of heat-assisted magnetic recording (HAMR) enabling 3.2 TB per platter with a roadmap to 5 TB and beyond.

By leveraging high-coercivity media and localised plasmonic heating, HAMR achieves stable, precise writing at atomic scales, pushing areal density to unprecedented levels while maintaining the industry-standard 3.5-inch form factor. 

How areal density drives efficiency, from disk platters to data centres.

Increasing areal density optimizes data centers and improves property ROI for new scale-out or managed fleets.

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 infrastructure ROI for new scale-out or managed fleets with higher per-platter density storage; for example, transitioning from 1 TB to 3 TB per platter allows a drive to achieve 30 TB capacity in the same form factor as a 10 TB drive. 

  • Drives with higher areal density deliver 2.6× better power efficiency per terabyte than current 10 TB 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.

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Areal density savings calculator.

Current hard drive

PMR


10 platters

Upgrade hard drive

HAMR


10 platters

PMR
67%
HAMR
67%

Acquisition cost savings per TB

PMR
74%
HAMR
74%

Embodied carbon reduction per TB

PMR
67%
HAMR
67%

Operational carbon and power reduction per TB

Areal density drives sustainable growth.

Innovations in areal density are indispensable for sustainable data centres, enhancing resource efficiency and reducing environmental impact.

  • Higher-density drives use fewer raw materials per TB, cutting manufacturing needs, energy use, and e-waste. 
  • Seagate’s roadmap to achieve 5 TB+ per platter in coming years enables scalable data growth while increasing sustainability. 

  • Improved areal density lowers carbon footprints by reducing drive counts and optimising embodied carbon in data centres. Drives with higher density deliver up to 3.5× better embodied carbon efficiency than standard 10 TB drives.

Seagate is leading the way.

As the world’s only hard drive manufacturer with areal density capabilities of 3 TB per disk, with 5 TB per disk on the horizon, Seagate is at the helm of a storage revolution. It starts with Mozaic 3+.

Exos M

The proven path to breakthrough areal density is here. Built to enable hyperefficient, sustainable data storage, Exos mass-capacity hard drives now feature Mozaic 3+, a powerful platform that unleashes areal density of 3 TB per disk so that you can store more exabytes in the same space for a significantly lower cost.