We test the peak power consumption of a NAS at the wall during a run of CrystalDiskMark 5.0.2 as this version of the benchmark runs the read and write benchmark suites separately so its easier to monitor what power the device is using during each function.
The AMD R-Series RX-421BD SOC in QNAP's TVS-673e has a configurable TDP range of between 12 – 35W. QNAP quote power consumption figures for the NAS with six 2TB drives installed (although there's no mention of whose disks) in the specifications of 35.11W in HDD standby and 63.69W in operation. The WD 6TB Red's we used in testing have a ratings of 0.4W standby/sleep, 3.4W idle and 5.3W active read/writes. However throwing a 10GbE card into the mix certainly doesn't help in keeping power demands low.