I'm not sure people here are getting the real picture.

Via Nano is a 20w TDP CPU.Atom is 2.5w for midis and 4-8w for desktops/embedded IIRC.

The tests featured a desktop Atom with a desktop board.

Had it been a mobile Atom ( 2.5w ) and a mobile board ( ~6w ) things would have been totally different.However , that's not the full story.

Nanon burns a healthy amount of power when loaded.Try to get its power to Atom like level ; I'd say the Atom will outperform it by 50% of more.

Nano really competes with low ( not even ultra low ) voltage dual core Penryns.Try 2GHz at 17w.We're talking same system power draw as Nano.Wanna bet who is going to win ?