Western Digital has long been a performance leader in the hard drive world. That made it especially odd when the company debuted its first terabyte in the "GreenPower" Caviar GP. Despite what enthusiasts might have hoped, GreenPower didn't mean "Hulk smash." Instead, it referred to the drive's eco-friendly motor, whose slower spindle speed dramatically reduced power consumption. WD had driven to the terabyte party not in a performance-oriented sports car, but behind the wheel of a tree-hugging econobox.

To be fair, the Caviar GP's performance was surprisingly good for a drive whose platters spun at close to 5,400RPM. In some tests, it was even faster than terabyte drives spinning at a full 7,200RPM. The GP also lived up to its energy-efficient billing, sucking half the power of some of its terabyte rivals, all while barely making a whisper.

Since its release, a reshuffling of Western Digital's hard drive branding scheme has transformed the Caviar GP into the Caviar Green. Now it's time for the drive itself to change. The original Caviar GP reached the terabyte mark with four 250GB platters, but the latest model we'll be looking at today has been upgraded to 333GB platters, of which it needs only three.The higher areal density of the Caviar Green's new platters promise improved performance, and since the drive is spinning only three of them, power consumption should drop as well. On all fronts, then, this latest Caviar Green looks better than the original. Let's see if it is.The idea behind the Caviar Green is a simple one. For some applications, be they home theater PCs, secondary desktop storage, or a home file server stuffed into a closet, you don't need the fastest hard drive on the block—just one that's fast enough. Those markets are likely to prefer drives with lower noise levels and power consumption, which the Caviar Green is more than eager to provide, ideally while maintaining an acceptable level of performance.

It might be counter-intuitive for an enthusiast to give up any performance, but the trade-off makes sense here. At least in consumer markets, most folks buy hard drives looking to expand storage capacity for their multimedia libraries. You don't need a fast hard drive to store or smoothly stream even the highest definition video content, and your multi-gig MP3 collection certainly doesn't need to be on a 10K-RPM VelociRaptor.

When it first launched the GreenPower Caviar, WD refused to disclose the drive's actual spindle speed, saying only that it was somewhere between 5,400 and 7,200RPM. The company later admitted that the drive ran at closer to the former than the latter, but we haven't been able to coax out an exact spindle speed.Numerous sites have speculated that the Caviar Green essentially runs at 5,400RPM, and now even Western Digital has changed its tune. Sort of. The drive's latest spec sheet lists the Green's rotational speed as "IntelliPower," which WD defines as "A fine-tuned balance of spin speed, transfer rate and caching algorithms designed to deliver both significant power savings and solid performance." So much for clarification.

Western Digital obviously doesn't want customers making assumptions about the Caviar Green's performance based on rotational speed alone, but the decision to obfuscate it behind blatant marketingspeak is entirely unnecessary and evasive. After all, the market isn't short on examples of drives with slower spindle speeds outperforming faster ones. One need look no further than our most recent mobile storage round-up to see Western Digital's own 5,400-RPM Scorpio Blue beating Seagate's 7,200-RPM Momentus in some tests. Consumers deserve a little more credit.
Enough with the soapbox, though. We have a drive to test. The latest addition to the Caviar Green lineup can be identified by its WD10EADS model number. You'll want to write that down, because the old drive's model number is WD10EACS. The drives themselves are quite similar, with the biggest difference coming on the platter front. Western Digital has replaced the original's quartet of 250GB platters with a trio of platters that weigh in at 333GB each. This 33% increase in areal density enables the Green to offer a terabyte with fewer platters, allowing the motor to spin less weight, which further reduces the drive's already low power consumption. The higher areal density of these new platters should also improve the Green's sustained transfer rates by spinning more bits past the drive head in a given span of time.