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Western Digital's Scorpio Black 750GB notebook hard drive

The best gets even better?

Manufacturer Western Digital
Model Scorpio Black 750GB
Price (street) $120
Availability Now

You can have the solid-state drive in my budget ultraportable notebook when you pry it from my cold, dead hands. Swapping in an SSD made the system noticeably snappier, and I much appreciate being able to throw the thing onto the couch or into a bag while it's mid-shutdown without worrying about disturbing a mechanical hard drive that's spinning my precious data at thousands of revolutions per minute.

The thing is, I can get away with a relatively affordable SSD in my notebook because it's really just a sidekick to the desktop that serves as my primary computer. I only need enough storage capacity for Windows, a handful of applications, a few gigabytes worth of work-related files, and enough casual games and BitTorrent downloads DVD rips to keep me entertained on a long flight. Accommodating all that on a 128GB drive is easy, and I could probably squeeze into 80 or 64GB without too much belt-tightening.

If your laptop is your primary computer, chances are you're using quite a bit more storage capacity. Big-name games take up an increasing amount of space these days, and the footprint of video archives is ballooning as high-definition clips become the norm. Don't forget years worth of digital pictures, a healthy helping of digital audio files, and the junk that accumulates in your "downloads" folder. Add it all up, and the solid-state route starts to look prohibitively expensive. 256GB SSDs cost more than most budget notebooks, and you'll pay well over a grand to get 400GB or more.

To put things into perspective, consider that Western Digital's Scorpio Black 500GB notebook drive costs a scant $70. A TR Editor's Choice award winner, the Scorpio is no slouch. It easily outperformed the competition in our recent round-up of 7,200-RPM notebook drives while offering longer warranty coverage and a lower price than its rivals. The only thing missing was a higher capacity point to match the additional storage offered by 640 and 750GB notebook drives currently on the market.

As it turns out, that deficit has been short-lived. At the Consumer Electronics Show just a couple of weeks ago, WD handed us a new Scorpio Black with 750GB of storage capacity—and said it was even faster than the 500GB model. Naturally, we were eager to put the drive through its paces in the Benchmarking Sweatshop. And so we have. Let's see if Western Digital has another Editor's Choice winner on its hands.

The first thing you should know about the Scorpio Black 750GB is that it uses the same 2.5", 9.5-mm form factor as the 500GB model. That's the standard size for notebook hard drive bays and slightly thinner than 12.5-mm variants of the 2.5" form factor designed for external enclosures. 12.5-mm drives are thicker to accommodate a third platter, but WD needs only two in the new Scorpio.

If you haven't already done the math in your head, each of the Scorpio's platters offers 375GB of storage capacity. That's a notable upgrade from the 250GB platters in the 500GB model. Each of those 250GB discs packs 400 gigabits into every square inch of surface area. The Scorpio's new platters have an areal density of 520 Gb/in², which is slightly lower than the 541 Gb/in² offered by the 375GB platters inside Seagate's Momentus 750GB.

Areal density is an important characteristic of mechanical hard drives because it affects performance on two fronts. The higher the bit density of the platters, the more data passes under the drive head with each revolution, increasing sequential throughput. At the same time, packing smaller bits more tightly makes each one harder to target when the drive head is darting across the platter accessing data that isn't laid out neatly on a single track. Perhaps that's why hard drive makers have largely stopped publishing random access time specifications for new models.

Western Digital is eager to boast about the Scorpio's improved sequential throughput, though. The 750GB drive has a maximum sustained data rate of 180MB/s, which is quite a bit faster than the 154MB/s quoted for the 500GB model. With a top speed that's still well within the capabilities of the 3Gbps Serial ATA spec, the drive has no need for a next-gen 6Gbps SATA link.

Scorpio Black 750GB Scorpio Black 500GB
Interface 3Gbps 3Gbps
Spindle speed 7,200 RPM 7,200 RPM
Cache size 16MB 16MB
Platter capacity 375GB 250GB
Areal density 520 Gb/in² 400 Gb/in²
Max sustained transfer rate 180MB/s 154MB/s
Idle acoustics 28 dBA 28 dBA
Seek acoustics 28 dBA 28 dBA
Idle power 0.8W 0.8W
Read/write power 1.75W 1.75W
Warranty length Five years Five years

The Scorpio Black does adopt one new standard: Advanced Format. Mechanical hard drives have traditionally organized data in 512-byte sectors. That was all well and good back when megabytes were a big deal. However, 512-byte sectoring wasn't really designed for a world in which terabyte hard drives are commonplace. For this data-rich reality, the storage industry has settled on a new Advanced Format scheme that segments drives into 4KB sectors.

By far the biggest problem with 512-byte sectors is that each one is sandwiched between blocks that contain data associated with data addressing and error correction. These blocks consume precious storage capacity and are still present with Advanced Format—they just appear every 4KB rather than every 512 bytes. The ECC block is actually a little larger with Advanced Format, but because it pops up less frequently, Western Digital says 4KB sectors can boost a drive's useful storage capacity by 7-11%.

Advanced Format can create problems for Windows XP, which was designed with 512-byte sectors in mind. Fortunately, WD supplies a free utility that will align partitions for optimal performance with the old OS. Windows 7, Vista, and recent versions of the Mac OS are already primed for Advanced Format.

All the fresh goodness baked into the 750GB iteration of the Scorpio Black really comes down to the platters—how much data they can store and with what sort of sector formatting. Otherwise, the new Black is pretty much identical to its forebear, right down to Western Digital's power consumption and acoustic specifications.

Frankly, we're a little surprised WD hasn't opted for a 32MB cache on this latest Scorpio. The company has long downplayed the benefits of larger caches, but that hasn't stopped it from slapping 64MB into its high-performance Caviar Blacks and low-power Caviar Greens. The fact that WD's competitors have yet to push beyond 16MB with their mobile products means no one has to keep up with the Joneses, I suppose.

Speaking of keeping up—or, rather, not—hard drive makers have been reluctant to match the five years of warranty coverage that Western Digital applies to its premium Black line. Seagate's Momentus XT mechanical/SSD hybrid is the only other notebook model we've seen with a five-year warranty. The rest are saddled with just three years of coverage.