Western Digital on Monday announced what it said is the industry's thinnest hybrid drive for Ultrabooks, a 5mm-thick model with 500GB of storage capacity.
The drives, equivalent to about one-fifth of an inch thick with a 2.5-in. form factor, feature hybrid technology, which combines spinning disk with NAND flash.
WD said it developed the new hybrid drive so it would be slim enough for integration into today's thinnest notebook PCs, which feature Instant-On and application performance similar to today's client solid state drives (SSDs).
The new hybrid technology will be showcased during WD's Investor Day, taking place this Thursday.
The new hybrid drive is aimed at notebooks using Intel's Ultrabook specifications. These specifications include Ultrabook Responsiveness Requirements, which set a higher level of performance than a notebook with a hard drive can offer.
In order to achieve higher performance, Ultrabooks must either have two drive bays, one for a hard disk drive and the other for a low-capacity solid-state drive (SSD) cache drive, or a single bay for a hybrid drive.
In a news release, WD stated that unlike dual-drive designs, its hybrid technology provides single-unit design homogeneity that Ultrabook system manufacturers "have long sought from the storage industry."
Hybrid drives, like Seagate's Momentus XT, use a small amount of flash as a cache element, to increase read and write performance.
WD declined to say how much NAND flash it is using in its hybrid drive.
Like Seagate's Momentus XT, WD's hybrid drive ports the operating system and most frequently used applications onto the flash memory, while files and other less frequently used data are stored on the hard disk portion of the drive. The result of systems' using cache SSDs is a lower cost laptop or netbook with the same or similar performance as a laptop with just an SSD.
The magnetic disk on WD's new hybrid drive backs up all files residing in the NAND, protecting the user from inevitable NAND wear and preserving it for the more hot data handling. WD's hybrid technology works in conjunction with the PC's operating system to deliver higher performance than current hybrid offerings while minimizing NAND wear to allow the use of less expensive MLC NAND.
Intel, Micron, and OCZ are putting out cache SSDs and Lenovo, Asus, Acer, Hewlett-Packard and Dell are beginning to build laptops and "Ultrabooks" to use them. For example, Lenovo's ThinkPad and ThinkPad Edge notebooks support cache SSDs, including models T420, T420s, T520, W520, X220, X1, Edge 220s, Edge 320, Edge 420, Edge 420s, and the Edge 520.
The Asus Zenbook UX 32VD combines up to a 500GB hard drive with a 24GB SSD.
WD began shipping 7mm thick hard drives for thin-profile notebooks earlier this year. Historically, standard notebook hard drives have been 9.5 mm.
The new 5mm hybrid hard drives offer 50 percent less volume compared to current 9.5 mm hard drives and at one tenth the cost of similar capacity SSDs, WD said.
"Acer is partnering with WD to bring advanced notebook performance and capacity in the smallest form factor," David Lee, associate vice president of the Mobile Computing Product business unit at Acer, said in a statement. "It's a part of our ongoing commitment to present leading technology that ultimately improves the total user experience of our customers."