In the summer of 2012 Western Digital unveiled its Red product series optimized for network attached storage devices. It is positioned by the manufacturer as optimal for entry-level and midrange NASes that can take in 1 to 5 HDDs. Corporate users are offered the WD RE series instead.
We might have expected a special series of NAS-optimized hard disk drives to come out sooner or later. Although WD’s Green HDDs are quite appropriate for this scenario, they, like most desktop HDDs, lack NAS-specific optimizations. The manufacturer mentions the following requirements to HDDs designed for NASes: 24/7 operation, optimizations for fault-tolerant RAIDs (error correction algorithms), multiple HDDs in a single housing (temperature, vibration). Unfortunately, most of these parameters are hard to check out in practice, so we have to trust the manufacturer that the firmware and design of the Red series is different indeed. We’ll limit ourselves to those parameters that we can study, such as data-transfer speed.
The Red series includes products with a storage capacity of 1, 2 and 3 TB. All of them have SATA 6 Gbps interface and 64 MB of cache. We’ve got 2TB products from three series for our today’s tests: WD Green WD20EARX, WD RE4-GP WD2002FYPS and WD Red WD20EFRX. Using full-featured WD RE drives instead of their energy-efficient counterparts seems to be overkill for home NASes, though, especially as such enterprise-class HDDs are considerably more expensive. We should also note that the Green and RE4-GP series have been around for a few years already, which is quite a long time for the dynamic IT market.
The manufacturer doesn’t specify the MTBF parameter for the Green series, but 750,000 hours has been mentioned earlier. For the RE4-GP and Red series the MTBF is specified to be 1,200,000 and 1,000,000 hours, respectively. The Green can last through 300,000 load/unload cycles whereas the other series are twice as durable. The Red features a higher operating temperature (up to 70°C) while the vibrations requirements are identical across all the series. All of them have IntelliPower in their specified rotation speed but that parameter is unimportant for home users.
From a practical point of view, the warranty period is much more important and the Green, RE4-GP and Red come with a 2-, 5- and 3-year warranty, respectively. In our tests we will check out their speed, power consumption and temperature in a high-quality 4-disk NAS.
The NAS is Synology’s DS412+ model with DSM 4.1 version 2668 firmware. It is one of the fastest NASes based on the Intel Atom platform. The client device is an Intel Core i5 PC running 64-bit Windows 7. The PC’s network card is connected directly to the NAS. Jumbo Frames technology is enabled.