Seagate today announced the third generation of its hybrid drive, the Momentus XT. This time around, Seagate has doubled the NAND flash to 8GB and increased capacity to 750GB.
Seagate also said the Momentus XT hybrid drive comes close to matching the performance of market-leading solid state drives (SSDs) that are more than twice as expensive.
Besides more memory and a faster drive interface, Seagate has added what it calls FAST Boot, which cuts a computer's boot time in half compared to the previous generation Momentus XT.
During an initial OS installation, the Momentus XT captures boot files and places them in a special segment of the NAND flash where they remain for the life of the drive. The feature ensures that the drive always boots from flash and not spinning disk.
The previous model Momentus XT was a combination of a two-platter, 7200rpm Serial ATA hard disk drive and 4GB of NAND flash and 32MB of DDR3 cache memory. Seagate did not provide read/write speeds on that drive. The previous Momentus XT could hold much as 500GB of data, although there was also a 250GB model with a retail price of $113. (The 250GB model has now been dropped from the company's line-up.)
The new Momentus XT also addresses issues with an overly aggressive Advanced Power Management tool that caused excessive spin downs with the previous drive. Seagate was forced to release a firmware upgrade on the last drive to deal with the problem.
The new Momentus XT is also a dual-platter model with greater areal density. The Momentus XT hybrid drive
According to Joni Clark, Seagate's product marketing manager, the company has switched NAND flash vendors. The new memory, she said, has 1.5 times better performance than the previous flash. Seagate also upgraded the drive interface from 3Gbps SATA to 6Gbps SATA.
Seagate said conducted performance tests against an Intel consumer-class 320 series SSD . Clark claimed the Intel SSD only beat the Seagate Momentus XT on boot times by 2 seconds. "The Intel SSD works out to $490 for 160GB. Ours costs [$245] for 750GB. For those two seconds [better boot up time], you'll end up paying an extra $300," she said.
Like the previous Momentus XT, the current model is a 4K sector drive, meaning it will not work well with Windows XT or earlier platforms; those OSes are tuned for 512Kbyte sector drives. Mac OS and modern Linux distributions are tuned to work with 4K sectors.
Unlike the second-generation Momentus XT, when Seagate only had computer-maker Asus as an early evaluator of the drive, the company has seven equipment manufacturers qualifying the drive for use in their systems. Those equipment manufacturers include Dell, Asus, Sony and Toshiba.
The new 2.5-in Momentus XT is aimed at higher-end laptops and desktops. "We're not talking necessarily about gaming systems, but maybe an $800 laptop as opposed to a $500 laptop," Clark said.
Clark said Seagate has also "tweaked" its Adaptive Memory algorithm for better performance. Seagate's Adaptive Memory software monitors what applications and data are first loaded into a system and then "learns" to place that data on the SSD to speed up performance. Over the course of three boot-ups, system performance becomes optimized to each user's preferences, Clark said.
Data is also copied first to the hard drive and then to the NAND; that ensures that if the NAND fails, data will not be lost. "If the NAND ever fails, you'll still have a perfectly good 7,200rpm hard drive," she said. "You'll still be able to boot up just like a regular hard drive, but you won't be able to take advantage of the NAND flash."
Copying frequently-used data to flash also means the SSD portion of the drive is almost always used for reads, not writes, which wears out NAND flash more quickly. The NAND flash also extends the life of the spinning disk, Clark said.
Lucas Mearian covers storage, disaster recovery and business continuity, financial services infrastructure and health care IT for Computerworld. Follow Lucas on Twitter at @lucasmearian or subscribe to Lucas's RSS feed . His e-mail address is email@example.com .
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