Western Digital Captures Capacity Lead With 1-TB Mobile Drive

Western Digital's new 1-TB WD Scorpio Blue mobile hard drive gives the vendor the crown for mobile computing storage capacity, but other high-capacity drives are better at pushing the performance envelope for mobile users.

Western Digital's new WD Scorpio Blue fits either 750 GB or 1 TB in a 2.5-inch mobile hard drive form factor for use in mobile PCs and portable storage devices, making them the first mobile hard drives to break the 1-Tbyte barrier.

When compared to the competition, the Scorpio Blue drives are the mobile capacity leaders. Seagate's Momentus mobile drive family maxes out at 500 GB, as does the Travelstar mobile drive family from Hitachi Global Storage Technologies (Hitachi GST).

But capacity isn't everything. Other drives are optimized for performance, including higher disk rotation speeds, larger cache memory or buffer size, and lower latency and read seek times, all of which help measure how quickly data can be accessed from the drives.

For instance, Western Digital's WD Scorpio Blue features a 5,200-rpm disk rotation speed, along with an 8-MB buffer size, latency of 5.5 milliseconds and an average read seek time of 12 ms.

This compares to Seagate's 500-GB Momentus 7200.4 mobile drive with a 16-MB buffer, a 7,200-rpm speed, 4.17 ms latency and 11 ms random read seek time.

While HGST's Travelstar E5K500 offers up to 500 GB of capacity, it has a 5,400-rpm rotational speed, an 8-MB buffer, an average latency time of 5.5 ms and an average seek time of 12 ms. The company's Travelstar 7K320 is faster, with a 7,200-rpm rotational speed, a 16-MB buffer, a 4.2 ms latency speed and a 12 ms seek speed.

Western Digital also competes with the best in terms of high-performing mobile drives. Its WD Scorpio Black features a 320-GB capacity, rotational speed of 7,200 rpm, a 16-MB buffer, latency of 5.5 ms and seek time of 12 ms.

The argument for capacity is easy. Mobile users are carrying more data, especially as they start combining their work and personal tasks on a single mobile PC. So, mixed on the hard drive along with the spreadsheets and PowerPoint presentations are home videos, photos and music, all hopefully backed up.

The argument for higher performance depends more on specific users' requirements. Certain mobile users such as gamers or heavy video users are looking for maximum performance, and capacity may be less of a priority.

However, high-performance mobile drives are just as likely to be used in non-mobile applications, such as RAID devices and blade servers where the low power consumption and low noise output compared to standard enterprise drives is a major consideration. Mobile drives may not have the same reliability, measured in mean time before failure, as enterprise drives, but for such applications are more than suitable.

So, capacity or performance? Both are needed, and both are available, just not always in the same package.