Source: Apple. 

Ever since Lenovo (OTC:LNVGY) launched its Yoga 3 Pro convertible laptop, I have been skeptical about whether Apple (NASDAQ:AAPL) would use Intel's (NASDAQ:INTC) Core M processor in a next-generation MacBook Air -- an idea I was initially quite fond of.

Indeed, if Apple were to use a Core M processor in its next MacBook Air, it would seemingly offer a performance regression from today's MacBook Air models utilizing 15-watt Core i5/i7 processors. The question, then, is whether Apple would accept such a performance regression in exchange for a sleeker design and fanless operation.

It's tough to believe, but not unprecedented
Apple has made it clear that it cares quite a lot about device performance. At the same time, however, the history of the MacBook Air shows the company has at times been willing to accept performance regressions in the name of battery life and/or form factor.

For example, in the "Mid 2011" MacBook Air, Apple ditched the discrete graphics chip and instead opted to use integrated graphics. This led to, in the words of AnandTech's Anand Shimpi , "a step back" in graphics performance relative to the "Late 2010" MacBook Air. It's worth noting, though, that performance elsewhere in the "Mid 2011" MacBook Airs improved upon the prior-year model.

Now, while the MacBook Air's 2011 and 2012 updates delivered massive jumps in CPU performance, the 2013 update was a bit different. CPU performance, according to AnandTech, was generally flat to slightly down relative to the prior year's model. In exchange, though, Apple brought a substantial boost in battery life.

Benefits beyond raw CPU and graphics performance
If Intel's low-power Core M processor can help Apple deliver an improved system-level experience, even if CPU/GPU performance comes down, then it wouldn't be far-fetched for a next-generation MacBook Air to use that chip family.

Intel's Kirk Skaugen has talked at length about how Core M makes a number of improvements at both the chip level and the platform level in order to drive much smaller logic boards. In this case, Apple could make a thinner design, allocate more of the system volume to the battery, and have a sufficient power budget to drive a higher resolution display.

On the bottom is the MacBook Air motherboard; on the top is a Core M motherboard. Source: Intel. 

These factors, particularly for the kinds of usage models that the MacBook Air targets, would likely far outweigh the performance decline seen in moving from the higher-power Core i5/i7 chips to the lower-power Core M. It would also drive more performance-hungry users to pay up for MacBook Pro models.

It's not clear which direction Apple will ultimately go in; fortunately, it probably won't be too much longer before the device is launched and Apple and iFixit tell us all about the innards of the device.