Since were talking power supplies.
Some cases appear to have good value but have cheap inefficient power supplies.
I say you can pay me now or pay for ever
It appears the specs for the psu on the above case is as follows
AL-8250SFX Suggestion Box
-Input range: 90V~132Vac or 180V~253Vac -Frequency: 47~63Hz -Input Current: 200W 6A/4A @ 115/230 Vac -Efficiency: 65% at full load
, nominal line.
That's at full load ... it's even less efficient at idle.
Not sure how many watts that turns into for your ATOM.
Give it a test maybe its not that bad
But my watt meter averages between 18-22 watts for all the ATOMS running in my house or sold at my web-store. An Other Pc's I suggest Plus 80 power supplies which are 80+ efficient even at idle.