WD Caviar Green 2TB & Seagate Pipeline HD 500GB: Two Very Quiet Drives

TEST RESULTS

Our samples were tested according to our standard hard drive testing methodology. The significant change in our testing procedure is that as of mid-2008, we're conducting most acoustics tests in our own anechoic chamber, which results in more accurate, lower SPL readings than before, especially as the SPL approaches 20 dBA and below, which is the territory of laptop drives. Our methodology focuses specifically on noise, and great effort is taken to ensure it is comprehensively measured and described. Performance is not tested comprehensively, for reasons discussed in detail in the methodology article. In essence, between similar drives, we feel the performance differences are trivial, while the noise differences can be significant. Furthermore, many other hardware review sites (such as The Tech Report, Anandtech, and X-bit Labs) do a good job of covering the performance (speed) aspects of HDDs, while none of them do a thorough job of noise analysis.

A. ACOUSTICS

Two forms of hard drive noise are measured:

1. Airborne acoustics
2. Vibration-induced noise.

These two types of noise impact the subjective perception of hard drive noise differently depending on how and where the drive is mounted.

Both forms of noise are evaluated objectively and subjectively. Airborne acoustics are measured in our anechoic chamber using a lab reference caliber microphone and computer measurement system. Measurements are taken at a distance of one meter from the top of the drive using an A-weighted filter. Vibration noise is rated on a scale of 1-10 by comparing against our standard reference drives.

A final caveat: As with most reviews, our comments are relevant to the samples we tested. Your sample may not be identical. There are always some sample variances, and manufacturers also make changes without telling everyone.

The WD drive was manufactured in February. Our Pipeline HD's date code correlates to a July 2008 manufacture date, according to our secret Seagate date-code decoder ring.

Ambient conditions at time of testing were 11 dBA and 20°C.

ACOUSTICS & POWER

Acoustically, these drives were the very quietest desktop models we've tested. The 2TB Green just edges out the 500GB Pipeline, both in terms of airborne noise and vibration. The Caviar Green's overall sound was broadband with very soft, low seeks that were only audible within a proximity of one to two feet. Both idle and seek with AAM enabled measured 13 dBA. Only when AAM was disabled did the seek noise produce a measurable difference, though our ears weren't sharp enough to differentiate the two modes.

The 500GB Pipeline had similar acoustic qualities, but with a touch more airborne noise — it sounded a bit louder and more hollow than the Caviar Green. The drive measured 14 dBA idle and 15 dBA during seek. Seek was significantly more noticeable — a cacophony of pitter patters like fast-falling rain. It is still very quiet for a desktop drive and easily disappears into the background with distance and/or increased ambient noise.

We derived some odd power consumption numbers with the WD drive. Idle and seek measured almost exactly the same, though idle power dropped significantly after the heads unload, which happens after approximately 7 seconds of inactivity — the same behavior that prompted WD to issue a firmware upgrade to increase the delay to prevent excess head loading/unloading. Our 2TB sample consumed less power during seek than our 1TB sample, but the opposite was true when idle, whether the heads were parked or not. The Seagate did very well, idling at only 4.8W.