[JohnBooty]

  They only started caring about power consumption when 
  it was already obvious to everyone that ARM is going to
  pose a threat to them eventually.

I'm being a bit pedantic, but it seems to me they refocused on power consumption beginning with the launch of the Pentium M (forerunner of the Core and Core 2 lines) which was released in 2003 and was surely in development several years before that.

Or do you think they were thinking ahead to ARM already in ~2001 or so? Maybe they were... although I think they were thinking about targeting laptop sales in general at that point, not ARM specifically.

[agumonkey]

That's true, the NetBurst syncope made them redesign toward efficiency, but still, the rise of ubiquitous mobility forced another inflection in their TDP curve. And they're still sweating over it since the PC market is shrinking and they need to get their foot in the smartphone/tablet market (see the bay-trail subsidize effort http://liliputing.com/2014/01/bay-trail-tablets-cheap-intels...)