So... i'm guessing the intel board does not supply enough power for my particular HDD?
It looks like this pairing is not supported.
But 1A isn't much. I suspect my 3.5'' drive used more than that, that Intel isn't talking about transient peaks and it would work fine... but I don't know. Do you want to take chances?
Look at the specs for the DH61AG and the DQ77KB (I hope I'm remembering the jumble of letters and numbers right).
More expensive, yes. But you get value for your money and with a Celeron CPU, the cost will remain reasonable.
To be honest, I'm more concerned with overall cost than I am with power consumption per se. Fanless operation isn't a must.
Then I would look at the used market.
If you're using a full PSU or are willing to source a pico:
Any Atom board from Pineview onwards is fine. Washu's D510MO would be an example.
Any low-power AMD board from Zacate onwards is fine.
And probably any low-end board for Intel CPUs from Clarkdale onwards would be a good choice too.
There are other options but I guess these would be the easier to pick. In case you find several interesting prospects, MSI and Intel used to be the best brands, efficiency-wise.
You can find DC-powered boards on the used market for a fraction of their price but it would probably require some patience and effort.
If you already have a normal power supply that you wish to use then look at the D2550MUD2 instead of DN2800MT. It's a bit cheaper, but likely uses a bit more power and doesn't have a mSATA slot.
If you couple it with your average PSU, it will use more than a bit more power!
There are very few PSUs with an efficiency at that kind of power draw that's comparable to a DC-powered board plus a decent AC/DC brick.