Look at the values I pointed at. What idle power consumption would you expect for Sandy Bridge dual-cores at idle with the H61 board based on the differences between CPUs with the P67 board? It is a plausible value? I think not.
They don't tell what PSU they used which makes their numbers dubious (these numbers can't be AC for the 880W you mentionned). Maybe they used a bogus correction for PSU inefficiency. My recollection is that they did so in other articles, with absurd results.
I start to see your point, but looking at charts 1 and 3 (Windows idling), at least for the PSU (in)efficiency: maybe it's worth to note that in their E-350 review, Xbit Labs declares the same PSU, an 80+ Bronze unit.
A tad suspicious, indeed: if it were as efficient as my Antec Signature (80+ Bronze), it should be under 55% at 15W AC level (230V), if it were as efficient as my Seasonic M12D (80+ Silver), it should be under 65% at same level/voltage... say definitely 55%? Let's try.
DC should be ~8W for the entire system: as an i5 draw just from the 12V line about 5W (according to Lost Circuits, a credible source for me, up to now) it doesn't sound fully right (even if I have read a 15W AC at idle for the 2100T from Missing Remote using - IIRC - an Antec 380W PSU), but comparing these figures with the 18-20W AC level recorded for Atom/Brazos by SPCR (with a PicoPSU 120!), it becomes even more suspicious.
Even about the difference between the P67 and H61, I see some further questions: in the only review with power data I was able to find about the H61 (TweakTown), the relevant board (Gigabyte mITX) draw 15W AC less than an H67 one (ASUS mITX) using the same 2600K CPU. If we add the ~20W DC usually draw at idle by the graphics card vs the presumable IGP power consumption, the difference should account for about 40-50W AC less than... (the Xbit declared) 45W AC for the G440+P67.
I'm not sure about my nightly math, but I have more doubts than before, now.