Tested: New Hybrid Hard Drives From Samsung and Seagate
When they were introduced a couple of years ago, hybrid hard drives seemed enticing. Pairing a standard hard drive with a flash component sounded like a good way to deliver on the theoretical performance boosts that flash can offer while still providing the long-standing price, capacity, and performance benefits of hard disks. We've now tested the first two hybrid hard drives to reach market, and we've discovered some clear benefits--but other results were inconclusive.
We looked at Seagate's Momentus 5400 PSD drive, announced today, and Samsung's SpinPoint MH80 drive, released this summer. Both models are 2.5-inch, 160GB notebook drives with 256MB of nonvolatile flash memory cache on board. The hard-drive industry concentrated on introducing the new technology in laptop drives because notebooks would be more likely to reap the benefits that hybrid tech promises, including faster boot time and power savings.
In the Test Center
The PC World Test Center examined the $190 Seagate Momentus 5400 PSD and the $299 Samsung SpinPoint MH80 alongside a $250 non-hybrid Hitachi Travelstar 7K200 (HTS722020k9SA00). We tested all three drives on a Dell Inspiron 1520, running a Core 2 Duo T7300 2-GHz CPU and 2GB of memory. Click the icon below to see a chart of our test results.
To test the hybrid drives, we did a fresh installation of the 32-bit version of Microsoft Windows Vista Ultimate and updated the drivers and BIOS. Surprisingly, we had to wait about 20 minutes for the operating system to recognize each hybrid drive. Once each drive was recognized, however, an NVCACHE tab appeared in the driver properties, and the drive was ready to work with Vista's ReadyDrive technology, which uses the drive's flash cache. You must run Windows Vista to use a hybrid hard drive.
To prepare the system to take advantage of any power savings the hybrid drive would provide, we entered the Power Options control panel and, under the Balanced power profile, changed the settings to enable the Windows Hybrid Hard Disk Power Savings Mode. Our experience was, in fact, much like that of someone who was upgrading their existing notebook with Vista and a hybrid hard drive.
The minimum requirements for using a hybrid drive are tied in with Vista's minimum requirements: Beyond having a system that runs Windows Vista and uses a Serial ATA interface, Seagate suggests that your PC have 2GB of memory, a dual-core or quad-core CPU, the latest BIOS revision (less than one year old), and the newest drivers. Seagate notes that hardware drivers can have an impact on a hybrid's benefits, though the company doesn't go into detail on this point in its reviewer's guide; when asked, the company stated that slow drivers can affect a PC's boot performance.
Power Savings Confirmed
The Hitachi drive is a performance model that spins at 7200 rpm, in contrast to the 5400-rpm speed of the Samsung and Seagate drives. However, the Hitachi model is representative of the direction notebook computing is going, as increasingly we're seeing mainstream and power notebooks with a 7200-rpm drive inside.
As such, it was no surprise that the Hitachi drive was the fastest at our timed hard-drive write tests. The Hitachi model required 154 seconds to copy 3.06GB of files and folders, versus the Seagate's 208 seconds and the Samsung's 217 seconds.
On our read tests, the difference was much smaller. The Hitachi required 25 seconds to search through its files, while the Seagate needed 29 seconds and the Samsung took 30 seconds. On our Panda virus-scan test of 6.12GB of files, the Hitachi and Seagate tied at 34 seconds, and the Samsung was just a shade behind at 36 seconds. Whether we can attribute those tight results to the hybrid models' use of 256MB of nonvolatile cache is uncertain, but the flash memory could be a factor.
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.