The idea that Core M can be fanless turned out to be some over-eagerness in Intel's marketing department. Not only does the Yoga 3 have a fan, it gets loud, and performance still sucks:
http://ultrabooknews.com/2014/10/16...erformance-tests-reveal-throttling-fan-noise/
Wouldn't bet on a fanless MacBook for another few years still. Not even really sure why this would be attractive either.
If you're annoyed by fan noise from the current MacBook, it means you are stressing out the processor. Would you rather it be quiet but much slower?
This is quite a fair point actually. The 12 inch size would be awesome but the core M and fanless design tbh is a step back in performance. Look at HP's new core M laptop supposed to be thinner then the air. I mean at what point does the thinness battle end. I would rather have the air the same thinness with more power efficient processors not slower.