Performance showdown: Flash drives vs. hard drives
- 01 May, 2008 07:24
Solid-state disks (SSD) are probably some of the most talked-about new gadgets of late. They easily distinguish themselves from the mechanical hard drives of the Jurassic period because they have no moving parts. Like USB drives, they use nonvolatile flash memory to store data, but SSDs are wrapped in an enclosure the size of a 2.5-inch mechanical laptop drive and have a SATA interface for an easy connection to the internals of your portable.
Having no moving parts is, naturally, important. There's no platter rotation or read/write head motion so SSDs -- in theory -- should use less power than equivalent mechanical hard drives. They should also (again, in theory) be faster than a mechanical hard drive at just about anything. Working off an electrical grid, there's no time wasted positioning the read/write head and then waiting for it to settle down and start doing its thing. SSDs just do it. (That's a bit of an oversimplification, but it's fair.)
So have you ever wondered if it's really worth it to plunk down the extra US$1,300 for an SSD-equipped MacBook Air? Or have you been tempted to swap the current mechanical hard drive out of your portable and slide one of these high tech bad boys inside? I did.
I sweet-talked Advanced Media and Crucial Technology into loaning me their 32GB SSDs and convinced Seagate Technology to hand over a sample of its 3.5-inch desktop and 2.5-inch laptop mechanical hard drives. When I got back to the lab and checked my pockets, the official list looked like this:
- 32GB Crucial Internal 2.5-inch SATA Solid State Drive
- 32GB Ridata 2.5-inch SATA SSD
- 250GB Seagate Barracuda 7200.9 3.5-inch SATA hard drive
- 200GB Seagate Momentus 7200.2 2.5-inch SATA hard drive .
To make sure I was working from an even playing field, I installed a fresh copy of Windows Vista Home Premium on the 3.5-inch desktop drive, fully updated the installation and then cloned that drive to each of the SSDs and the 2.5-inch mechanical Seagate drive using Apricorn's DriveWire hard drive adapter and Easy Gig II hardware/software package. The software uses dynamic partitioning, making the differences between the 250GB, 200GB and 32GB devices irrelevant. Vista Home Premium occupied about 12GB of space.
Surprising performance results
I used HD Tach to test the drives' performance -- and got some interesting results. It was the mechanical Momentus drive that scored the highest burst speed at 214.3MB/second. The Crucial SSD came in second at 137.3MB/second, but the desktop Barracuda and its 135MB/second clung to its heels. Advanced Media's Ridata drive trailed the pack at a leisurely 71.2MB/second While the two mechanical drives and the Ridata SSD posted average reads in the 54MB-to-55MB/second range, Crucial forged ahead at 120.7MB/second.
SSDs are highly praised for their boot speed, so I would have been remiss had I relied solely on a standardized test. The results were a bit surprising. Crucial's SSD and the two Seagate devices all required 39 to 40 seconds to cold boot to the desktop. (There are a few minutes of behind-the-scenes activity during a Vista boot, but I determined that the boot was complete once the Windows sidebar appeared.) Ridata did best of them all, with a boot time of 32.1 seconds, although that's hardly the blazing speed you might expect from an electronic versus a mechanical device.
I then timed each drive during a system restart. Restarts are different than cold boots in that Vista logs you off and then closes any running processes before it starts the reboot sequence. The Crucial drive did the worst here, taking 78.4 seconds to complete. Ridata posted the best time at 54.8 seconds, but the Momentus laptop drive needed only 55.6 seconds. Even the big, dinosaurish Barracuda ran through the paces at 59.9 seconds. Again, this is hardly the overwhelming speed difference that's been expected for SSDs.
Finally, because these SSDs have a comparatively small capacity, it's most likely that you will be transferring data from your laptop after a day's work. So I took 4,666 files and folders (a total of 8.05GB) and copied them to the drives and then copied them from those drives. I used the same secondary drive as source and destination in all cases.
Neither of the SSDs fared very well when having data copied to them. Crucial needed 243 seconds and Ridata took 264.5 seconds. That's over four minutes. The Momentus and Barracuda hard drives shaved nearly a full minute from those times at 185 seconds. In the other direction, copying the data from the drives, Crucial sprinted ahead at 130.7 seconds, but the mechanical Momentus drive wasn't far behind at 144.7 seconds. Ridata and the Barracuda were third and fourth at 156.8 and 166 seconds, respectively.
None of these results, in my opinion, show any clear and present advantage to these SSDs -- at least not on a price/performance ratio. I'd have to be in a severely time-critical situation to justify spending an extra US$550 just to shave seven seconds off the cold boot time (or 1.7 ounces in weight). Even so, I'd lose that boot advantage when it came to transferring files from the drive.
So forgive me for being contrarian, but while I recognize the exotic and alluring nature of solid state disks as a technology -- and have certainly fallen victim to their potential "wow factor" on occasion -- after spending 12 days with a pair of them and a pair of mechanical drives, I'm, convinced that SSDs have yet to live up to their true potential.
Bill O'Brien is a freelance writer who has written a half-dozen books and more than 2,000 articles on computers and technology, including Apple computers, PCs, Linux and commentary on IT hardware decisions.