You’ve undoubtedly heard about the craze of “green” hard drives from companies like Western Digital and Seagate. They promise that these drives will consume less power and cost less (since they only run at 5400RPM or 5900RPM), but from what Ars Technica reports, these “green” drives don’t differ all that much from regular drives.
“In terms of cost, using a green hard drive compared to a normal one makes very little difference. Assuming your drive spends 4 hours reading and writing and 20 hours idle per day, switching from the WD Black to Green saves you only 45 kilowatt-hours per year. The national average cost of a kilowatt-hour is 11.93 cents, netting you a whopping $5.38 per year for your sacrifice of 1800 RPM. For comparison, changing one 60-watt lightbulb used 4 hours a day to a 7-watt fluorescent one saves you more, about $9.23 per year.”
They’re obviously not completely useless since they’re still relatively quieter and stay cooler than regular drives, making them ideal for HTPCs and backup storage.