"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."
Rydning sees a healthy market for hybrid drives because PC market dynamics dictate improvements in performance and price, which hybrid drives offer. SSDs remain too expensive for most manufacturers to include in their systems.
IHS iSuppli analyst Fang Zhang agreed. He said most consumers purchasing a $700 PC or laptop aren't going to spend hundreds of dollars on an SSD. So SSDs will continue to be reserved to a niche market of high-end applications and users.
"SSDs are still way too expensive," she said. "They're at least 10X what hard drives cost."
According to iSuppli, cache SSDs, however, offer more advantages than hybrid HDDs. For instance, discrete cache SSDs and hard disk drives are much more scalable and efficient for mainstream storage, given the broad selection of drive manufacturers. And because SSDs and HDDs have lately been focused on more mobile sizes, few changes are needed for cache SSDs or thin HDDs to keep their manufacturing processes cost effective.
Additionally, the expected evolution of cache SSDs to a swappable mSATA form factor not only helps narrow the convenience advantage currently enjoyed by hybrid HDDs but also allows them to be upgraded like DRAM modules or USB drives.
HDDs sized 7mm are available with 500GB in 2.5-inch platters, with a 5-mm z-height as the next step, while hybrid HDDs are still 9-mm high. SATA SSDs are also getting denser, and NAND on the motherboard is becoming more feasible, iSuppli said in its report.
"Cost concerns, longer design cycles and tighter engineering tolerances in the case of hybrid HDDs also add to their difficulty of use in ultrabooks," iSuppli stated.
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