I’ve tested with asrock n100dc-itx motheroard, one stick of 16GB ddr4, samsung pm961 256GB NVMe. I’ve powered the HDD with motherboard power cable.
I’ve looked into my older tests with very similar motherboard, hl15 chassis and quite good corsair rm550x power supply. Idle power efficiency tests - #3 by ynfh26jy
If I’m crunching my number correctly power draw in these tests came out as:
~9,5W for Ultrastar 7K4000
~9W for 20TB WD DC HC560
There may be some overhead from running test in a server chassis with passive backplane.
I cannot get near specsheet 6W idle in any realistic testing scenario on this HC560.
Maybe Toshiba drives are better. I’ll try to get my hands on one of these at some point.