Analysts Predict Skyrocketing SSD, Cache Drive Sales, But What Happened To Hybrid Hard Drives?

According to IHS iSuppli, the SSD market will continue to boom this year, thanks to the rapid rise of so-called cache drives. These drives -- we reviewed a 60GB example from Corsair last month -- are popular with OEMs because they pair a small amount of NAND flash with a traditional hard drive.

We aren't surprised to see cache drives taking off in desktops, but their popularity in notebooks is a little harder to parse -- particularly when you consider that Hybrid Hard Drives, like Seagate's Momentus XT, have been on the market for several years. While Seagate's HHDs aren't necessarily as fast as a cache drive + HDD combo, OEMs tend to favor solutions that allow them to integrate functionality.

iSuppli predicts that while HHD sales will double by next year, cache drives will surge a whopping 2,660%, to 23.9 million units, before blowing through the 67.7 million-unit mark next year. The bulk of the market will still be based on spinning media -- hard drive sales in the first quarter of 2012 hit 145 million units.

The advantage of cache drives is that they allow OEMs to offer SSD-like performance while using between 8-60GB of Flash. Even at the upper end, that's half the 128-256GB drives that have proven popular with consumers. In our own review of the Corsair Accelerator Series, many of you mentioned being unsure whether or not SSDs would prove as reliable as HDDs long term; pairing the two solutions together is one way to assuage customer fears over long-term data retention.

"The cache SSD solution was first hit upon by PC manufacturers because the use of a dedicated solid-state drive proved too expensive when passed on to consumers in the retail market," said IHS iSuppli analyst Ryan Chien, analyst for memory & storage at IHS. "However, a combined physical hard disk drive with a smaller cache component allowed PC makers to reap the advantages of faster responsiveness and larger capacities while keeping costs down."

According to John Rydning, hybrid hard drives are less popular due to single-source manufacturing (Seagate has the only solution on the market) and a lack of options. Right now, the Momentus XT is only available in a 2.5" form factor that's 9.5mm high. It also offers less Flash, and only accelerates read performance.

"The other part of it is there's probably more than can be done to improve system performance with hybrid technology; I'd say they have not had a lot of [computer manufacturer] design wins," Rydning told PCAdvisor, referring to manufacturers who buy the drives wholesale from Seagate. "Seagate has done OK selling them in the aftermarket. In a sense, that's allowed them introduce them to the market and it's allowed Seagate to learn as well."

The odd thing about the nascent HHD market is precisely that we've seen so little work done by the traditional HDD manufacturers. Western Digital's VelociRaptor series, for example, would seem an ideal test case for hybridization -- while that drive may not be headed for ultrabooks, a hybridized version of it could offer best-in-class HDD performance without sacrificing capacity. HDD manufacturers have posted strong profits in the wake of the Thailand floods last year, but that won't last forever unless they take steps to incorporate performance-enhancing features.