Western Digital Caviar Black and RE4 2 TB Hard Disk Drive Review
By Gabriel Torres on September 30, 2009
Until very recently the only 2 TB hard disk drives available on the market were “green” models, rotating at lower speeds in order to save energy, like Seagate Barracuda LP and Western Digital Caviar Green. Western Digital has finally released two 7,200 rpm models, Caviar Black (targeted to desktops) and RE4 (targeted to servers). Let’s take a look at the performance from these new drives.
Hard drives typically consume between 8-10 W; “green” models consume practically half of this. The trade-off is obviously performance: since they rotate at lower speeds “green” drives present lower performance. Drives from this category are mainly targeted to external enclosures that are going to be connected to the computer through a USB or FireWire port. Since this kind of port limits the drive performance, the hard disk drive doesn’t need to be the fastest around and thus you can save money both on the cost of the drive and on your electricity bill.
Drives targeted to the enterprise segment (i.e., servers), on the other hand, have a higher reliability, as required for this market segment, with some manufacturers providing extended warranty contracts with the drive. With some enterprise-class drives, for example, the manufacturer can ship a new drive in case of failure before the client sends the defective drive to them, reducing the down time of a server.
2 TB hard disk drives have a real capacity of 1.82 TB or 1,863 GB (3,907,029,168 sectors). As you may be aware, the capacity advertised by hard disk drive manufacturers isn’t the real drive capacity. Read our Hard Disk Drives Capacity Limits tutorial for further information on this subject.
Here is a summary of the hard drives we are going to compare:
Western Digital does not inform at what speed their Caviar Green drives spin; 5,400 rpm is our educated guess.
Prices were reasearched at Newegg.com on the day we published this review. We couldn’t find Western Digital Caviar Black 2 TB being sold yet.
Seagate announced last week the launch of their first 7,200 rpm 2 TB hard drive, Barracuda XT, which is based on the new SATA-600 interface, doubling the available bandwidth. All the other drives are based on the SATA-300 interface. We will post a review for Barracuda XT as soon as it becomes available.
Now let’s compare the performance from these four 2 TB drives.
During our tests we used the configuration listed below and the only variable component between each benchmarking session was the hard disk drive being tested.
We adopted a 3% error margin. So, performance differences below 3% cannot be considered meaningful. In other words, products where the performance difference is below 3% must be considered as having similar performance.
Usually we use three programs to evaluate hard disk drive performance, DiskSpeed32, HD Tach and HD Tune. DiskSpeed32, however, would freeze exactly in the middle of the data gathering process and our best guess is that this program isn’t compatible with 2 TB drives. Thus unfortunately we had to keep it out of our benchmarking process.
HD Tach provides only two results, the burst transfer rate and the average transfer rate. We ran the “long bench” test from this program.
On the burst transfer rate measured by HD Tach Western Digital RE4, Caviar Black and Caviar Green achieved the same performance level, being, on average, 8% faster than Seagate Barracuda LP.
Average transfer is certainly the most important parameter for the regular PC user and on HD Tach the new Western Digital RE4 and Caviar Black achieved the same performance level, being, on average, 18% faster than Seagate Barracuda LP and 42% faster than Caviar Green. Here we can clearly see the huge impact of the rotational disk speed on the drive’s performance.
If you are interested, you can find below the read curves plotted by HD Tach for the hard disk drives tested.
Now we have the results provided by HD Tune.
Here Seagate Barracuda LP was the fastest drive, being 10% faster than Western Digital Caviar Black, 11% faster than RE4 and 23% faster than Caviar Green. Caviar Black and RE4 achieved the same performance level, being 12% faster than Caviar Green. Keep in mind that the burst transfer rate measures the maximum transfer rate between the motherboard SATA port and the hard disk drive controller located on the drive itself, and may not represent real-world performance.
Here once again Western Digital RE4 and Caviar Black achieved the same performance, being 17% faster than Seagate Barracuda LP and 41% faster than Caviar Green.
Here once again Caviar Black and RE4 achieved a similar performance, being, on average, 13% faster than Barracuda LP and 41% faster than Caviar Green.
The minimum transfer rate is achieved when the hard drive is reading data from its inner-most tracks.
Here RE4 was a little bit faster than Caviar Black (6%). RE4 was 23% faster than Barracuda LP and 44% faster than Caviar Green, while Caviar Black was 16% faster than Barracuda LP and 36% faster than Caviar Green.
If you are interested, you can find below the read curves plotted by HD Tune for the hard disk drives tested.
Access time is another important measurement. It measures the time the hard disk drive delays to start delivering data after the computer has asked a given data. It is measured in the order of milliseconds (ms, which is equal to 0.001 s) and the lower this value, the better.
The results presented by the two programs were slightly different, so this time we plotted a chart showing the two programs.
Western Digital RE4 and Caviar Black achieved exactly the same access time. According to HD Tune they achieved an access time 21% better than Barracuda LP and 32% better than Caviar Green. According to HD Tach they achieved an access time 19% better than Barracuda LP and 33% better than Caviar Green.
The new 7,200 rpm 2 TB drives from Western Digital, RE4 and Caviar Black, achieved the same performance level. They are a lot faster than the 2 TB “green” models, making them to be the right choice if you are looking for a 2 TB drive. The correct drive to choose will depend on the computer you are going to install it, a server (RE4) or a desktop (Caviar Black).
Price is still an issue. Although we couldn’t find Caviar Black for sale on the main on-line stores, it has a suggested price of USD 300. The 1 TB version from Caviar Black costs only USD 100, so if you are worried about performance you should buy two 1 TB drives and install them in RAID0 – and you will still save USD 100! Of course if you are building a computer with tons of terabytes of storage space using 1 TB drives you will need twice the number of drive bays to achieve the same capacity as if you were using 2 TB models.
Also the competition is heating up, as the first 7,200 rpm 2 TB drive from Seagate to arrive on the market, Barracuda XT, comes with the new SATA-600 interface (which provides double the available bandwidth – keep in mind that this does not necessarily mean that this drive is faster, this only means that the interface is capable of exchanging data faster, actual performance will depend on the drive) and with the same price tag.