It sounds like all they did was lower the spindle speed to lower the wattage.
3TB uses like 5.4 watts (7200rpm)
4TB uses like 5 watts (5900rpm)
New specs of 4.8 watts sounds like they increased the efficiency and lowered the power consumption but lowering spindle speed (5400rpm ??? )
I hate 5400rpm
Give me 10,000rpm
Or 7200rpm Decreasing the spindle speed is a very stupid way to lower power consumption that wreaks havoc on performance. The difference in actual real electricity cost of half a watt in the real world is not worth the performance penalty.
let's examine the cost of a 5.5 watt HDD versus a 4.8 watt HDD:
5.5 watts for 7200rpm 3TB HDD multiplied times 24 hours a day = 132 multiplied again times 365 days a year = 48,180 watts consumed. Divided by 1000 = 48.18 kwh's annually.
4.8 watts for 5400rpm 3TB HDD multipled times 24 hours a day = 115.2 multiplied again times 365 days a year = 42.048 watts consumed. Divided by 1000 = 42.048 kwh's annually.
My local utility sells power to me @ .07315 per kwh. (7.3 cents)
48.18kwh's for the 7200rpm = $3.52
42.04kwh's for the 5400rpm = $3.07
- - - - - - - - - - - - - - - - - - - - - - - - -
Now, I am not sure I did the math right so if I did it wrong please correct me. But I think the difference between a 7200rpm and a 5400rpm drive in actual dollars per year spent on electricity is very, very small. It's certainly not worth spending more for a lower power consuming drive as you will never recoup the extra cost of the purchase price. Once I factor in I must live with a lower performing drive the cost/benefit ratio just isn't there for me to be a believer in lower spindle speeds. The fact the lower more energy efficient drives often sell for more $$ (like WD RED or WD GREEN, or these new NAD Seagate drives based on MSRP amount) it's just not worth it over a cheaper, better 7200rpm everyday HDD.
This entire argument gets compounded and increases my passion for the 7200rpm drive once I factor in that a 3TB WD GREEN drive @ 5400rpm actually consumes the same amount of electricity as a 3TB 7200.14 Seagate that runs circles around it in performance. (both about 5.4watts) RED is basically the same story. It looks like the newest models (like these new Seagate NAS models) are the most efficient available and even with those newest and lowest power consuming drives there is very little difference in electricity costs per year to run them. The performance penalty is not worth it to me.
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. Using a higher average from top states total 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. That's comparing a very energy pig like 9 watt Black drive to a green 5 watt drive, and using a much higher rate per KWH than I am currently paying. (Almost twice my rate)
Once you start seeing 3TB 7200.14's using within a watt of the consumption of a slower spindle speed drive it make no sense at all to me. I'd never want one in a desktop, or a server. Perhaps if I had a crappy NAS box that was limited in performance to 40MB/sec based on inferior hardware I'd say it doesn't matter, but then again I'd probably never buy something like that.
Originally Posted by AnandTech
Seagate decided that the performance loss of moving to 5900RPM wasn't justified by the power savings. It believed that by introducing a more power efficient 7200RPM drive it could deliver the best of both worlds, negating the purpose of the Green line. For most desktops, Seagate has a point. The couple of watts you save by slowing down the motor aren't really realized in a system that idles at 60W and can consume over 100W under load. On the other hand, the performance drop is definitely noticeable. Hard drives have pretty bad random access performance to begin with, and slowing spindle speed isn't going to help.
Good article on the fallacy of "green" drives with lower spindle speeds. ^