Original URL: http://www.theregister.co.uk/2009/10/07/review_storage_wd_caviar_black_2tb/

WD Caviar Black 2TB

Two terabytes of performance HDD

By Leo Waldock

Posted in Hardware, 7th October 2009 12:02 GMT

Review The 2TB Caviar Black is the second hard drive we have seen with a capacity of two terabytes. Glance back to our 2008 round-up of 1TB drives, which used three or four platters, and you can see that this is pretty much a doubling of areal density.

Western Digital Caviar Black 2TB

Western Digital's Caviar Black 2TB: covered up...

The first 2TB drive we saw was a member of WD’s Caviar Green line-up with an emphasis on environmentally friendly performance. The key here is power draw so the Green drive uses a lowly spin speed of 5400rpm despite the inevitable performance hit.

It’s a different story with the 2TB Caviar Black which has a spin speed of 7200rpm along with a host of other features.

The guts of the Black are similar to the 2TB Green as both models use four 500GB platters with eight read/write heads. However, the extra spin speed has made some changes necessary. For starters, the cache has doubled in size to 64MB. Every drive in the Caviar Black family is described as having "up to 64MB", but to date the only drive we have seen with that much memory is the 2TB - smaller drives have 32MB.

The most dramatic new technology is the twin actuator, and it's currently unique to the 2TB Black. Actually, that’s not quite true as the 2TB Black shares all of its features with the WD RE4, which is an enterprise drive.

Western Digital Caviar Black 2TB

...and nekkid

The specification of the RE4 is very similar to the Caviar Black in every respect except that it has an MTBF rating of 1.2 million hours while there is no mention made about the expected life of the Black. Both drives have a five-year warranty. The other difference is that the RE4 is intended for use in Raid and as a result the TLER (Time Limited Error Recovery) is much lower. A desktop drive will typically attempt to recover bad sectors for 15 seconds while we understand that the RE4 will quit after seven seconds.

The dual processors that control data flow in the Caviar Black are common to all of the drives in the Black range and so too are the StableTrac and NoTouch features. These are, respectively, a mounting system that supports both ends of the motor shaft and a way of ensuring the heads don’t make physical contact with the platters.

Dual actuator technology is the result of a reworking of the end of each actuator arm:

Western Digital Caviar Black 2TB

Instead of mounting the read/write heads directly on the actuator arm, WD has added an extra component to the system. The read/write heads are mounted on a piezoelectric actuator that in turn is mounted on the arm. This means that the head can move across as many as five tracks while the arm remains in one position.

During our testing we found that the 2TB Caviar Black compares very favourably to the 1TB Black. File transfer speeds within the 2TB drive are considerably faster than the 1TB which suggests that the increases in cache, areal density and head reach flexibility have worked wonders. HD Tach shows that random access time has dropped by a healthy margin while read and write speeds have all improved to the tune of 20 per cent. CrystalDiskMark also shows a marked improvement for the 2TB drive.

HDTach 3 Readout
WD Caviar Black 2TB

WD Caviar Green 2TB

Western Digital Caviar Black 2TB

Click each image for a full-size version

This is thoroughly good news but of course it’s the combination of performance allied to the colossal 2TB capacity that catches the eye. That said, the formatted capacity is a ‘mere’ 1863GB.

2GB File Copy Results

Western Digital Caviar Black 2TB

File duplication time in Seconds (s)
Shorter bars are better

HDTach 3.0.1.0 Results
Random Access

Western Digital Caviar Black 2TB

Random Access Time in Milliseconds (ms)
Shorter bars are better

HDTach 3.0.1.0 Results
Average Data Speeds

Western Digital Caviar Black 2TB

Speeds in Megabytes per Second (MB/s)
Longer bars are better

The problem, however, is that you’re paying a whopping great premium of £50 for the Black drive compared to the 2TB Green. Alternatively, you can buy the 1.5TB Green for £87 which sounds like something of a bargain compared to the £150 2TB version, let alone the £204 Black.

The other problem for WD is that Seagate has just announced its new 2TB Barracuda XT with 6Gb/s Sata interface. This is very tempting if you’re building your PC around a new Intel P55 motherboard as it has a 6Gb/s Sata controller. The Barracuda XT is priced at the same level as the Caviar Black so WD's 3Gb/s Sata drive might be seen as the end of an era.

We also wonder how long it will be before we can make the transition from great big clunky 3.5in drives to slinky 2.5in units. WD has recently released a Scorpio Blue laptop drive with a capacity of 640GB which is a slimline 9.5mm drive that only contains two platters.

Western Digital Caviar Black 2TB

Speeds in Megabytes per Second (MB/s)
Higher points are better

You can also buy triple platter 12.5mm Scorpio Blue drives with capacities of 750GB and 1TB, so it seems likely that small form factor PCs will soon be offered with a choice of SSD or 2.5 inch HDD.

Toshiba and others have 640GB-and-up 2.5in HDDs on the way too.

Western Digital Caviar Black 2TB

End of an era?

Verdict

WD has done sterling work to boost the performance of the Caviar Black with an increase in both data cache and areal density. The result is a speedy 2TB drive that unfortunately costs more than £200. ®

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