We measured the power consumption of the drives both when idle and when under load. We used a random write test with average block sizes of 4 kB and 1 MB as our load test.
The Barracuda Pro 12TB is already one of the most efficient drives in idle and this test clearly shows that it is related to its 10TB-brother. Under load this new drive shows it is the most efficient hard disk drive in this test. Considering its bigger storage capacity this is quite the performance.