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Five 2.5-inch hard drives at 500GB


Take your half-terabyte to go
— 11:58 PM on June 4, 2009

SSDs have stolen much of the limelight in the hard drive world. Depending on who you ask, these high-performance arrays of flash memory chips either represent the future of PC storage or a major bifurcation in the industry. For now, however, solid-state drives are largely confined to the fringes. Although they're slowly gaining a following among performance-hungry enthusiasts who live on the bleeding edge, SSDs have yet to make major inroads among mainstream users, even in the mobile world.

Notebooks are about as close to home court as it gets for solid-state drives. For one, the overwhelming majority of consumer-grade SSDs conform to a 2.5" form factor compatible with all but the thinnest and lightest of ultraportable systems. The mobile world is also where the superior shock tolerance and lower power consumption inherent to flash-based storage pay the biggest dividends. And let's not forget that 2.5" mechanical hard drives don't pack nearly as much capacity as their 3.5" counterparts, giving SSDs less of a storage gap to bridge.

In fact, SSDs have already matched the capacity of the roomiest notebook drives on the market. Today's 2.5" mechanical drives top out at 500GB, which is just a smidgen less storage than 512GB SSDs currently for sale. But there's a catch. You're going to pay north of $1,500 for a 512GB SSD, which works out to nearly three dollars per gigabyte. That lofty cost per gigabyte isn't confined to premium capacity points, either. Lower-capacity SSDs typically run two to three dollars per gigabyte, with more expensive models pushing a whopping four bucks a gig.

So what about those 500GB mechanical notebook drives? Today, they're available for between 26 and 17 cents per gigabyte. Most will set you back less than a c-note, which, in the SSD world, buys just 32GB.

The fact that traditional hard drives offer better value, on a cost-per-gigabyte basis, than SSDs is certainly not surprising. Solid-state drive prices may be falling, but they still have a long way to go. What is surprising is the fact that the highest capacity 2.5" mechanical hard drives on the market are so inexpensive.


Unlike 3.5" desktop drives, where manufacturers' flagship models are strung out between one and two terabytes, 500GB is the highest 2.5" capacity offered by Hitachi, Samsung, Seagate, and Western Digital. No wonder prices are so competitive. But that raises the question: with all the major players lining up at the same capacity, which drives stand out? To find out, we've gathered 500GB flavors of Hitachi's Travelstar 5K500.B, Samsung's Spinpoint M7, Seagate's Momentus 5400.6 and 7200.4, and Western Digital's Scorpio Blue for a good old-fashioned throw-down.

As you've surely noticed, we have two drives from Seagate. That's because the Momentus manufacturer is the only drive maker currently selling 500GB notebook drives at both 5,400 and 7,200 RPM. Spindle speed counts for a lot with mechanical storage, giving the Momentus 7200.4 a significant advantage right out of the gate. The fact that the 7200.4 also features 16MB of onboard cache memory—twice what's available from the rest of the field—certainly raises our performance expectations for the drive. It also raises the question of why other manufacturers haven't bumped their drives up to 16MB. They may be sticking to 8MB at 5,400 RPM to further differentiate future 7,200-RPM models.

All five of the drives we're looking at today measure a scant 9.5 mm thick, which doesn't leave a lot of room to stack rotating platters. There are only two discs per drive, and as you might expect, each weighs in at 250GB. It's amazing how areal densities escalate these days. Just a year ago, the highest-capacity notebook drives packed a mere 160GB per platter.

Hitachi Travelstar 5K500.B Samsung M7 Seagate Momentus 5400.6 Seagate Momentus 7200.4 Western Digital Scorpio Blue
Interface speed 300MB/s 300MB/s 300MB/s 300MB/s 300MB/s
Total capacity 500GB 500GB 500GB 500GB 500GB
Capacity per platter 250GB 250GB 250GB 250GB 250GB
Cache 8MB 8MB 8MB 16MB 8MB
Spindle speed 5,400 RPM 5,400 RPM 5,400 RPM 7,200 RPM 5,400 RPM
Average seek time 12 ms 12 ms NA NA 12 ms
Max media data rate 109MB/s 138MB/s 147MB/s NA NA
Idle power 0.8W 0.85W 0.81W 0.67W 0.85W
Read/write power 1.4W 2.5W NA NA 2.5W
Seek power 1.7W 2.5W 1.54W 1.55W NA
Idle acoustics 2.4 bels 2.4 bels 2.4 bels 2.3 bels 2.4 bels
Seek acoustics 2.6 bels 2.6 bels 2.6 bels 2.6 bels 2.6 bels
Warranty length 3 years 3 years 3 years 3 years 3 years
Street price

While manufacturers tend to disclose platter counts, spindle speeds, and cache sizes, not all are keen to publish the intimate details of their drives' performance characteristics. Seagate, for example, makes no mention of Momentus random access times on the drives' data sheets. While the company posts a maximum media transfer rate for the 5400.6, it doesn't do so for the 7200.4. Of course, Western Digital doesn't publish media transfer rates at all. But that matters little, because we can test such things ourselves. The benchmark results on the following pages should illuminate each drive's performance characteristics with much greater clarity than best-case theoretical peak specifications on a datasheet.

Power consumption is a key metric for notebook drives, since watts saved can extend battery life. The drives look to be on relatively equal footing, with the 7200.4 quoted for lower power draw than one might expect from a 7,200-RPM unit. We'll see if that holds true in our own power consumption tests.

Three years of warranty coverage is the de facto standard for consumer-grade hard drives, and none of the bunch deviates from that mark. Western Digital does offer a five-year warranty on its 7,200-RPM Scorpio Black drives, but those have yet to spin a half-terabyte.

All four of the 5,400-RPM models we're looking at today are available for less than $90 online, which makes them quite evenly matched. The Momentus 7200.4 commands a hefty price premium of nearly 40%—a tall order for its faster spindle speed and larger cache to make up.

Before moving on, I should mention a couple of optional features available on some of these drives. Versions of the Hitachi and Seagate units are available with free-fall sensors that provide an extra measure of protection against accidental droppage. The Spinpoint M7 has a free-fall sensor, too, but Western Digital only offers this feature on its Scorpio Black drives—not on the Blue. Hitachi's Travelstar can be ordered with a Bulk Data Encryption option for those prone to losing laptops loaded with classified state secrets, social security numbers, and credit card information in public places. Full-disk encryption is available from Seagate, as well, but not on these particular Momentus models. Neither Western Digital nor Samsung offer encryption options for their notebook drives, although Samsung has launched self-encrypting SSDs.