Western Digital Preps its 28TB HDDs Based on ePMR and UltraSMR

Western Digital will soon sample its 28TB HDDs for data centers and hyperscalers. Leveraging advanced recording technologies, including energy-assisted perpendicular magnetic recording (ePMR) and UltraSMR, these drives will offer substantially higher platter track density. Existing designs will employ them to increase areal density and reduce track size without changing the core drive design.

At the end of the fiscal fourth quarter, we have successfully qualified all variance of our 22 terabyte CMR and 26 terabyte Ultra SMR hard drive platforms at all major cloud customers, setting the stage to improve shipments and profitability.

In addition, we are about to begin product sampling of our 28 terabyte Ultra SMR drive. This cutting-edge product is built upon the success of our ePMR and Ultra SMR technologies with features and reliability trusted by our customers worldwide. We are staging this product for quick qualification and ramp as demand improves.


According to WD, UltraSMR can improve write efficiency by 20%, allowing the upgrade of 24TB HDDs to 28TB UltraSMR drives. Unlike UltraSMR, ePMR is a multi-generational technology bridging the gap between PMR and HAMR. The company is shipping 26TB UltraSMR drives to select clients before rolling it out to the general market.

Western Digital plans to adopt a combination of different technologies till HAMR becomes the standard. From 20TB to 30TB+, the drives will be built using ePMR, UltraSMR, and OptiNAND. This means that the 28TB SKU will be going up against Seagate’s 32TB HAMR drives, which will likely be faster and denser. Customer satisfaction and drive reliability will be WD’s key allies here.

Areej Syed

Processors, PC gaming, and the past. I have written about computer hardware for over seven years with over 5000 published articles. I started during engineering college and haven't stopped since. On the side, I play RPGs like Baldur's Gate, Dragon Age, Mass Effect, Divinity, and Fallout. Contact:
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