Western Digital divides their internal hard drives into three
distinct families - the WD Caviar Blue for their basic hard drives,
the WD Caviar Green for their quieter, cooler hard drives and the WD
Caviar Black for their performance-grade hard drives.
According to Western Digital, Caviar Green hard disk drives offer an
average power saving of 4-5 watts over their competitors, a feat that
they claim is equivalent to reducing CO2 emissions by 13.8 kg per
year. Of course, that's a mere drop in the ocean but if you can help
save the environment while you work or play on your computer, why not?