Temperatures And Power Consumption
The 4 TB Black drive brings up the rear when it comes to measuring temperatures, posting 41 degrees Celsius and tying Hitachi's Deskstar 7K4000 as the warmest disk in our line-up. Then again, 41 degrees is still acceptable, particularly in a desktop machine with plenty of airflow.
In contrast, though, Western Digital's WD30EFRX (from the Red family) manages a frosty 31 degrees, which is why it's marketed as the right drive for network-attached storage appliances, which are usually loaded with other drives also generating heat.
If you're looking specifically for low power consumption, then the WD4001FAEX is certainly not the way to go. Western Digital doesn't even try to hide the fact that its five-platter 7,200 RPM flagship is a bit of a power hog. The company's data sheet lists an idle power number of 8.1 W, which is actually worse than the 7.9 W we recorded.
The 4 TB Black model shows us 8.1 W of power use during HD video playback and 9.3 W during a maximum write speed benchmark, doing nothing to redeem the high idle consumption result.
As a result, when we look at performance per watt, Western Digital's new 4 TB monster falls to the bottom of our chart.