The Quarks (rip) had a reduced and improved x86-compatible instruction set and they were quite low powered... they really failed to catch on because Intel didn't think to put them in a friendly package to be integrated into anything - they thought teeny tiny pitch BGA was fine for the Maker community that still loves their throughhole components. (And they were kinda buggy chips, but they had roughly shaken them down well by the next silicon spins). I had kinda hoped the Quark would stick around, just so Intel could start sundowning some of those terrible old instructions and execution modes and start properly decrufting x86 - it's 2018, we don't need 32-bit Real Mode anymore, we can emulate it a thousand times on a PC and still have processor power left to play video games.

But, that being said, these things probably have a "Mobile Core" processor (i.e. an Atom), which are quite low powered still, and they probably don't run them at all that high of a clock rate either, saving more power.