Western Digital Caviar Green 2TB (WD20EADS) internal hard drive

Western Digital has managed to fit 2TB of storage in a single hard drive. The Western Digital Caviar Green 2TB (WD20EADS) has a competitive cost per gigabyte of storage, although there are faster hard drives available.

The Western Digital Caviar Green 2TB has an areal density of 400 gigabits per square inch, and its four platters hold 500GB of data each. It is equipped with a 32MB cache and has an interface speed of 3Gbps. The drive has a formatted capacity of 1.81TB, delivering a competitive cost per gigabyte of 26 cents.

There are faster hard drives, such as the Seagate Barracuda 7200.11 1.5TB. But that isn't to say the Western Digital Caviar Green 2TB is especially slow. This was demonstrated during testing with HD Tune Pro, which showed an average read speed of 78.1 megabytes per second, an average write speed of 77.5MBps and a burst rate of 126MBps. By comparison, the Seagate Barracuda 7200.11 1.5TB scored a read speed of 94.6MBps, a write speed of 98.4MBps and a burst rate of 147MBps. (The burst rate is the highest speed that data can be transferred from the cache to the system.)

We conducted some real-world testing as well, transferring 18GB of data between the Western Digital Caviar Green 2TB and our test bed PC, which uses a Western Digital Velociraptor (WD3000GLFS).

We recorded a read speed of 50MBps and a write speed of 61.66MBps. Both of these speeds are respectable in their own right but slower than the average 72.91MBps achieved by the Seagate Barracuda 1.5TB.

The results from our copy transfer test, where we transfer the data from one location on the drive to another, were more positive with the 2TB drive achieving an excellent speed of 33.295MBps.

HD Tune Pro also revealed the Western Digital Caviar Green 2TB has an access time of 14.7ms. This encompasses the drive's seek time, transfer time, spin-up time and rotational delay, and is slightly slower than the Seagate Barracuda 1.5TB's access time of 13.9ms. To put this into perspective, the high-performance Western Digital Velociraptor (WD3000GLFS) has an access time of 7ms.

Some of the drive's slower performance is probably due to the hard drive being designed to be "green", which involves a number of processes aimed at minimising noise, temperature and power consumption levels. The most significant of these is the IntelliPower function, which controls the speed to optimise power usage. Western Digital does not disclose the number of revolutions per minute (rpm) the Caviar Green 2TB can achieve, and the IntelliPower function can't be disabled.

Our tests showed that the drive was able to run at 34°C, which is between one to two degrees below the average operating temperatures of the Seagate Barracuda and Western Digital Velociraptor.

Although the WD Caviar Green 2TB's cost per gigabyte of 26 cents is 5 cents more than the Barracuda 1.5TB drive's 21 cents, it's still great value for this amount of storage in a single device. Because the hard drive is new, you can expect prices to start dropping very soon as the competition catches up.

If you're after a whole lot of storage in a single hard drive, you can't go past the Western Digital Caviar Green 2TB.