I found this - http://www.asrock.com/mb/Intel/Q1900DC-ITX/
"DC Adapter Saves More Energy
Compared to other counterparts, this motherboard is powered by DC adapter and able to reduce power consumption by a maximum of 50% when idle and 38% at full loading! Without traditional PSU, you can save a lot of energy and be more friendly to our environments."
This looks like BIG difference.
I think that the Seventeam ST-201MQ 200 watts used in the comparison it is not a good PSU.
This is just a commercial spot for sell the Q1900DC-ITX board.
Using a 80 Gold PSU with 88% efficiency the difference in power consumption between Q1900DC-ITX and Q1900-ITX is not much.