Energy consumption Here is the data for energy consumption for each of the drives that we were able to read with a clip-on ammeter, by reading voltages used on the 5V and 12V lines.
In load the 3-platter WD20EARS scores lowest here at just 2.7 watts. The 7200 rpms draw a good deal more, from 6.8 to 7.1 watts. In load, the Caviar Black consumes 10.8 watts while the EcoGreen F4 draws just 5.6 watts.
We then measured the temperature of the drive after 1 hour of intensive use in IOMeter. These measurements were taken with the HDD outside of the casing, with room temperature at 25°C without the fan, each of the drives slightly raised. The temperature was measured in two places using an infrared thermometer, above the middle of the drive and at the hottest point on the left side. We also read the temperature on the internal drive sensor (SMART).
In these conditions the WD Caviar Black gets fairly hot in spite of the low ambient temperature and it would be a good idea to make sure you’re using a sufficiently effective fan if you go for one of these. The Barracuda XT is however fairly cool for a 7200 rpm model. The drives that stay coolest are the 5400/5900 rpm drives, which were all recorded at around the same temperatures.
To take this we placed each drive so as to avoid all vibrations (seeing as they were placed on the desk). A sonometer was placed 10 cm above the drive so as to measure noise pollution, the PC used being without any fan so as to isolate the sound of the drive.
In rotation, the 7200 rpm drives are the noisiest, with the Barracuda XT scoring highest. The 7K2000 is the noisiest during accesses, just 0.1 dBA ahead of the Caviar Black. Quite a bit of noise is generated here and this is something you need to weigh up against the Caviar Black’s reduced access times.
The quietest drive is the 3-platter WD20EARS, closely followed, in rotation, by the EcoGreen F4. The EcoGreen F4 is however much noisier during accesses.