Slim hard drives no threat to SSDs for tablets

Hard-disk drive (HDD) makers are introducing smaller form factor devices to cash in on fast-growing tablet sales but the road to success in this market segment is bumpy given the dominance of solid-state drives (SSDs), analysts warned.

Increasing shipments of SSDs for tablet devices over the next few years, although just a tiny fraction compared to HDDs, are expected to "shave off points of market share that are critical to maintaining the growth of the hard drive business", Fang Zhang, analyst for storage systems at IHS iSuppli, noted in a research note last month.

The research firm predicted that SSD shipments for notebooks will grow from 4.7 million in 2010 to 16.8 million units in 2015. This is, however, expected to represent only a single-digit percentage of the notebook storage market. At the same time, the growth of media tablets--where the storage option is primarily flash memory--will negatively impact sales of notebooks, and hence the HDDs in them, it added.

To stave off the challenge from SSDs, HDD manufacturers are looking to undercut the cost of SSDs while providing higher densities--in the form of slim spinning disks, Zhang reported, citing Seagate's Momentus Thin as an example.

The U.S.-based analyst also told ZDNet Asia in an e-mail interview that Hitachi and Toshiba have announced thin or 7-millimeter (mm) HDD versions, and such drives are targeted at notebooks, netbooks and external storage devices.

Slim HDDs, said Zhang, cost between US$40 to US$50 for capacity of 320 gigabytes (GB) to 500GB--"far less" than SSDs, which typically cost US$88 for 64GB.

Slim HDDs face uphill task
However, the near term opportunity for these hard drives in tablets is limited, she pointed out. According to IHS estimates, HDD-based models will account for 2 percent or less of the total tablet market in 2012.

Gregory Wong, president of Forward Insights, concurred. "HDDs will have a struggle in tablets. [Apple's] iPad has set the standard using NAND flash in tablets," he explained in his e-mail.

At 7mm, slim HDDs are still about twice as thick as a modular SSD, Wong added. The space savings SSDs provide increases if it is in a BGA (ball grid array) form factor. In addition to the space reduction, flash drives offer power savings, better performance, and instant-on capability, he said.

IHS' Zhang also noted several disadvantages of HDD-based tablets, including potentially shorter battery life, longer boot time and a relatively heavier device compared to SSD-based tablets. "These drawbacks may serve as a disincentive to some tablet users who require speed and mobility."

However, she observed that appeal of HDDs in media tablets will grow if the flash component is increased at the motherboard or processor level. This would improve performance previously afforded by SSDs, and manufacturers can then turn to the cheaper HDD option for storage purposes, she explained.

Seagate Technology, on the other hand, believes that slim HDDs are a "compelling option for tablet manufacturers and buyers" as they provide the "best cost-performance values". Momentus Thin, which is included in the Archos G9, offers users 250GB of capacity--eight times more than a standard 32GB tablet--at the same cost, a spokeswoman pointed out in an e-mail.

Noting that some in the industry believe that SSDs will begin to mass replace HDDs in laptops in the coming years, she argued that even though demand for storage in personal computing will continue to rise, NAND flash production is not keeping up.

"NAND flash memory production capacity is forecast to grow to 21 exabytes in 2011, with about 2 exabytes--9 percent--going to solid-state drives and the rest to smartphones and other consumer devices," the spokesperson said, citing a December 2010 Gartner report.

She added that worldwide installed fab capacity is expected to grow from 11.5 exabytes in 2010 to 21 exabytes in 2011--a "staggering" 82 percent.

"Yet even at that impressive [more than] 80 percent growth rate, with the vast majority of the NAND going to consumer devices, the yawning gulf between NAND flash memory production capacity for solid state drives and demand for laptop storage will continue to widen," the Seagate spokesperson stated.

Gartner on Thursday revised downward its forecast for the semiconductor industry in 2011. The research firm said worldwide semicon revenues will drop 0.1 percent against 2010 levels. However, it noted that NAND flash will continue to enjoy over 20 percent year-on-year growth, driven by strong sales of smartphones and Apple's iPad.

Seagate added that it expects SSDs to remain niche in the laptop market "until it reaches the right mix of cost per gigabyte and performance".

Over at Western Digital (WD), which does not yet have a slim HDD, its Asia South sales director Margaret Koh said the company is "evaluating the interest in such a product and would enter the market should our customers demand it". It presently sees HDDs and SSDs as "complementary for a long time forward", she added.

"Each technology offers different attributes, benefiting respective applications. HDDs are a better choice for any application [needing a capacity] larger than very small. That covers the majority of mass storage applications today and in the near future," Koh explained.

"SSDs offer favored attributes when the host device is very small and requires only low capacity; and where ultra performance is critical, such as in enterprise applications. WD would offer what customers demand for each application."

Best of both worlds
Seagate's spokesperson noted that SSDs will be geared toward the enterprise environment, in which transactional performance is key and cost per gigabyte secondary. HDDs will drive the company's storage for the consumer space, she added.

Another segment the company sees as an answer to user needs is the solid-state hybrid drive, which combines SSD speed with HDD storage capacity--at an HDD price. Its Momentus XT, launched in May 2010, has crossed 1 million in shipments, according to a company statement last month.

Forward Insights' Wong also pointed to hybrid combinations in "ultrathin laptops and ultrabooks".

"A combination of a low-capacity SSD plus HDD will offer price points and capacities better than a SSD, at a performance better than a HDD," he said.