The Impact of Flash Memory
The flash memory definitely had an impact in our power tests. Here, we particularly noticed that the hybrid hard drives produced systemwide power savings in system-idle mode. The Seagate drive caused the PC to draw 5.2 percent fewer watts than the Hitachi; with the Samsung drive, the power saved was slightly less, but still statistically significant, at 4.2 percent fewer watts. Our results align with what the manufacturers told us: In hybrid drives, power savings occur when the magnetic disk spins down and parks its heads. When this happens, the flash cache kicks in, and the system instead pulls data from the flash memory.
Our boot-up tests, unfortunately, were inconclusive. Although proponents say hybrid drives can improve boot-up time by as much as 30 percent--as more files get pinned over time to the nonvolatile flash cache--we did not see a consistent trend in boot times on either the Seagate unit or the Samsung model. Over the course of ten boots, the Seagate hybrid drive varied from a high of 44 seconds (boot five) to a low of 34 seconds (boots four and eight). The Samsung drive varied from a high of 38 seconds (boot one) to a low of 34 seconds (boot seven). And the Hitachi drive was right up there with similar numbers: a high of 38 seconds (boot one) and a low of 35 seconds (boot seven).
We are still conducting WorldBench 6 Beta 2 tests on these drives. When those tests are completed, we'll update this story with the results.
Hybrid Future Watch
While the benefits of hybrid drives may remain unclear, the technology does carry a price advantage over competing solid-state drive (SSD) technology, notes Melissa Johnson, Seagate product marketing manager. With hybrid technology, says Johnson, "you can get faster boot-up time and lower power for a fraction of the premium you'll pay for SSD. That's why we feel hybrid will be a mainstream player in the mainstream notebook market." Seagate also plans to sell solid-state drives.
These first-generation hybrid drives incorporate only 256MB of NAND flash, a pittance in comparison with the 2GB USB flash drive you can buy today for $20. But the memory in the older drive is typically multilevel cell flash (MLC) as opposed to the more reliable--and more expensive--single-level cell flash (SLC) that hybrid drives, as well as SSD models, use. Manufacturers say they decided on 256MB of flash in hybrid drives as an entry point that wouldn't throw the cost of the product out of whack when compared with the cost of a standard 2.5-inch hard drive.
Andy Higginbotham, director of sales and marketing for Samsung's Hard Disk Drive Group, notes that NAND flash's cost per gigabyte is expected to decrease by about 50 percent per year. Considering that timeline, Higginbotham says, we can expect to see hybrid hard drives incorporate 512MB of flash in 2008, 1GB of flash in 2009, and 2GB in 2010--all for the same cost as integrating 256MB today.
While both Samsung and Seagate will sell drives for upgrading an existing notebook, you can also buy a laptop preconfigured with a hybrid hard drive. Sony's VAIO SZ650 notebook ships with Seagate's hybrid drive inside; three other notebook manufacturers are in the process of qualifying the Seagate drive for use in a laptop PC. Samsung's drive is available for sale from CMS Products.