Testing The Western Digital Black² Dual Drive

The Testbed

Testing Methodology

We tested in both Windows 7 and Windows Vista, with the latest updates. We chose to use IO Meter 2008 as well as our "old faithful", WinBench 99 2.0, with the following tests :

• Platter Data Transfer Profile
• Business Disk WinMark 99
• High-End Disk WinMark 99
• Disk Transfer Rate (Beginning)
• Disk Transfer Rate (End)

Business Disk WinMark 99 is a real-world simulation based on three office application suites - Microsoft Office 97, Lotus SmartSuite and Corel WordPerfect Suite 8, as well as a web browser, Netscape Navigator. They are quite dated, but should still reflect the usage patterns of users in an office environment using such applications. The test runs through a script that keeps multiple applications open, while it performs tasks that switches between those applications and Netscape Navigator. The result is the average transfer rate during the script run.

High-End Disk WinMark 99 is a real-world simulation based on AVS/Express 3.4, FrontPage 98, MicroStation SE, Photoshop 4.0, Premiere 4.2, Sound Forge 4.0 and Visual C++ 5.0. However, it differs by running the applications serially, instead of simultaneously. There are individual results for each application but in this comparison, we will be looking only at the weighted average score, which is the average transfer rate during the tests.

Unfortunately, WinBench 99 is not fully compatible with Microsoft Windows 7, registering a SetFilePointer error in the Disk Access Time test. So, we were not able to obtain any Disk Access Time results.

In addition, it would keep crashing if the hard drive was tested with a single partition. This is likely due to a limit on the size of the partition that is supported by WinBench 99. We came up with a workaround by dividing the hard disk drive into 5 partitions of equal sizes. We then tested each partition individually and averaged the results.

Usable Capacities

The Western Digital Black² Dual Drive has a 120 GB SSD with 8 GB of overprovisioning, and a 1 TB HDD with an official formatted capacity of 1,000,204 MB. We checked that out by formatting it in NTFS using Microsoft Windows 7.

The SSD has a formatted capacity of 119,898,370,048 bytes. This is 101 MB less than the official formatted capacity. With about 97.6 MB allocated to the NTFS file system, the usable capacity was about 119.8 GB.

The HDD has a formatted capacity of 1,000,204,136,448 bytes. This is 204 MB more than the official formatted capacity. With about 124.6 MB allocated to the NTFS file system, the usable capacity was very slightly (79.5 MB) more than the official capacity of 1,000 GB.

Maximum Surface Temperature

We monitored the surface temperature of seven hard disk drives during their benchmarks. The following chart shows their operating temperature range, from idle to maximum load. Please note that instead of giving you the absolute numbers, we are showing the temperature delta, which is the difference between the actual temperature and the ambient room temperature.

Not surprisingly, the Western Digital Black² Dual Drive was the hottest mobile drive in this comparison. It is two drives in one, after all.

Even when it idles, it is hotter than the 240 GB Intel 520 Series at full load. This is borne out by the fact that even when it idles, it consumes almost a watt of power. In fact, it also consumes the same amount of power in standby and sleep modes.

The 1 TB WD Blue Slim (WD10SPCX), which forms the HDD component of the WD Black², consumes just 0.57 watts while idling and 0.18 watts in standby or sleep modes. The WD Black²'s much higher power consumption must therefore be due to its SSD component.

According to the official specifications, the WD Black² consumes just 1.8 watts while reading or writing, or just 0.1 watt more than the WD10SPCX. However, that doesn't mesh with our temperature tests. It's possible that the 1.8 watt specification was when a single drive was active, not both at once.

Transfer Rate Profile (SSD)

Unlike hard disk drives which deliver a wide range of transfer rates, solid state drives have an almost uniform transfer rate across the entire device. Here, we compared the Western Digital Black²'s SSD component to 240 GB Intel 520 Series and the 160 GB Intel X25-M G2 (34 nm) solid state drives.

Even though Western Digital only rated the Black²'s SSD with a maximum read speed of 350 MB/s, our tests show that the IMFT flash memory used is really capable of delivering throughputs of about 390 MB/s. That makes it about 12.5% faster than the Intel 520 Series SSD and 39% faster than the Intel X25-M G2 (34 nm) SSD. Of course, this doesn't determine the actual real world performance, because we haven't factored in the performance of the SSD controller.

Transfer Rate Profile (HDD)

We compared the Western Digital Black²'s HDD component (the WD10SPCX) to its 500 GB brother, the Blue Slim (WD5000LPVT) as well as the older WD10JPVT. The WD5000LPVT is basically a single platter version of the WD10SPCX, while the WD10JPVT uses 3 platters (instead of 2) and does not use the Advanced Format Technology (AFT).

The maximum platter transfer rate appeared to be about 118 MB/s which progressively dropped across the platter to about 57 MB/s at the last track. The platter quality seems to be reasonably good in this sample, with only 18 visible dips which would suggest the use of replacement sectors.

Despite the higher-density 500 GB platters, the WD10SPCX boasts only a slight boost in transfer rate over the WD10JPVT, which uses 333 GB platters. The small performance difference decreased as we moved from the outer tracks to the inner tracks.

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