In some follow up testing not document with a chart, I also checked out network transfers to/from a USB 3.0 drive attached to the DS212. I was interested to see if the Super Speed USB connection could be accessed over the high speed network connection, to make expanding the capacity of the NAS easy and impressively quick. Unfortunately, 13MB/s was about the maximum I was able to achieve in such a manner, which initially seemed like a problem to me. But, testing the same USB 3.0 hard drive connected directly to my router produced results maxing out at 7MB/s. The DS212 can access USB 3.0 drives for high speed transfers, it just can't share them with the network at full speed.
Power consumption testing was the next item of interest. The specifications provided by Synology indicate power consumption of 18.2W during disk access, which seems kind of generic to me, so I wanted to see how close the configuration with two 3TB drives could get to that. With each NAS device taking a turn plugged in to a Seasonic Power Angel monitoring device, I monitored the idle power consumption and the active power consumption. Idle conditions consisted of the NAS having no activity from network transfers or extra internal processes running. The active conditions consisted of copying a batch of MPG movie files from the drive while simultaneously running the CrystalDiskMark benchmark on it.
The chart below details the results, and while it wasn't quite as energy efficient as the numbers indicated by Synology, it did perform very well!