WD 2TB Caviar Green Versus 2TB Caviar Black

Many consumers and enthusiasts are looking for massive storage capacities, and the perfect solution for this is a 2 TB hard drive. These massive drives offer plenty of capacity for storage-intensive programs and space-hungry operating systems, like Windows 7 x64, with plenty of room left over for photos, music, and HD video content. It also makes perfect sense to use as a storage drive on a system that uses a Solid-State Drive (SSD) as the primary drive. With many SSDs suffering from performance degradation it also makes sense to off-load some of the data to a good old fashioned hard drive as they are reliable, inexpensive and come in much larger capacities.

On September 1st, 2009, Western Digital announced two new 2 TB hard drives that belong in the Caviar Black and RE4 series, which are 3.5" hard drives that feature four 500 GB platters. The WD Caviar Black 2 TB (model WD2001FASS) and WD RE4 2 TB (model WD2003FYYS) hard drives feature 7200 RPM spin speed, 64 MB cache, dual stage actuator technology, SATA 3 gigabits per second (GB/s) interface, and an integrated dual processor to deliver ultimate performance in a maximum-capacity drive. WD¡¯s RE4 2 TB drive is designed for enterprise-class applications, so we won't be looking at that one today. We will be looking at the brand new WD Caviar Black 2 TB (model WD2001FASS) hard drive and will be comparing it to the WD Caviar Green 2 TB (model WD20EADS) hard drive. Here is a quick chart showing some of the differences between WD's four 2 TB hard drive offerings.

The WD Caviar Green and Black hard drives might look identical on the outside other than the label, but internally the drives are actually very different. Western Digital has added some new technology inside the 2TB Caviar Black hard drive to increase the drive's performance.  One of the main additions is a dual state actuation (DSA). This is a head positioning system with two actuators that improves positional accuracy over the data track(s). The primary actuator provides coarse displacement using conventional electromagnetic actuator principles. The secondary actuator uses piezoelectric motion to fine tune the head positioning to a higher degree of accuracy and speed as it decreases the short seek times by ~0.4 ms. This is only available on the 2 TB Caviar Black and 2TB RE4 hard drives.

The dual state actuation and constant 7200 RPM spindle speed make the 2TB Caviar Black louder than the 2TB Caviar Green. Western Digital does not disclose the spindle speed (RPM) on any of their Green series of drives as they are variable speed.  WD uses an IntelliPower (a fancy name for an algorithm), which is based on things like power and cache usage, to determine what speed the drive should be spinning at. The WD website states that it could be anywhere from 5400 RPM to 7200 RPM depending on what state the drive is in.  As you can see from the table below, the 2TB Caviar Green this does impact noise levels.

The Caviar Black is 4 dBA louder at idle and 4-5 dBA louder during certain seek tests, so you have to take this into account when purchasing a hard drive.  If you are building a silent system that has no fans the Caviar Black is going to stick out like a sore thumb, but in a gaming system you won't be able to hear it over many fans used on CPU coolers and video cards. 

Flipping the drives over you can see that the PCB revisions are close to being identical, but there are some small differences that can be seen just above the bar code.  The WD 2 TB Caviar Black uses dual processors to maximize performance versus just one on the 2 TB Caviar Green. Let's take a quick look at the test system and move on to the benchmarks to see how big of a difference features like this mean.