Conclusion

The improved 2 TB Western Digital Caviar Green (WD20EARX) is sadly a fumble for Western Digital. Despite the new SATA 6 Gbps interface, it is actually slower than its predecessor, the WD20EARS, which is ostensibly similar in all but the slower SATA 3.0 Gbps interface. However, the truth is quite different.

Our tests revealed that the new WD20EARX has a slightly slower spindle speed than the WD20EARS. This is likely to be the main cause for its poorer performance, as well as its lower power consumption and thermal output. When coupled with the performance-sapping effect of the drive's AFT emulation mode, this results in a rather slow hard disk drive.

Like all newer Western Digital high-capacity hard disk drives, this model supports the Western Digital-pioneered Advanced Format Technology (AFT). However, this is not full-fledged AFT drive as it still uses 512-byte emulation for compatibility reasons, and therefore appears to be a regular hard disk drive to the outside world. Due to the use of an emulation mode, there are performance ramifications, of course. You can read all about it here - The Western Digital Advanced Format Performance Comparison Guide.

Even if your motherboard has a built-in SATA 6.0 Gb/s controller, we cannot recommend the new WD20EARX. You would actually do better with the older WD20EARS - it may use the slower SATA 3.0 Gb/s interface but it is definitely faster than the new WD20EARX, thanks to a higher spindle speed.

Forget about the faster SATA 6.0 Gbps interface. Both Caviar Green hard disk drives run at just above 5400 RPM with maximum throughputs that will not saturate even the slower SATA 3.0 Gb/s interface. Therefore, the faster SATA 6.0 Gbps interface have very little effect on the WD20EARX's performance.

Of course, you may not mind the slower speed - it has the indirect benefit of a lower thermal output. However, you should not pay a premium for the faster interface. Get the WD20EARX only if it's the same price (or cheaper) than the WD20EARS. If the WD20EARS is cheaper, then the choice is as clear as day and night - get the WD20EARS.

For the lowest current prices on Western Digital Caviar Green hard disk drives, click here!

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