Back in June 2013, Apple (NASDAQ:AAPL) launched the current iteration of the MacBook Air. This device was highly praised for its extremely long battery life and good performance, enabled in no small part by Intel's (NASDAQ:INTC) just-launched Haswell processor. In April 2014, Apple updated the MacBook Air to include slightly faster Haswell processors and slashed the price of the entry model to $899 from $999.

While Apple's Mac sales continue to be strong,  probably driven in part by share gains against Windows-based machines, the company is probably eager to be able to refresh its Mac in a more substantial way than it did during 2014. After Intel's announcements at its investor meeting, I think a reasonable guess as to when the new MacBook Air will launch is now possible.

Broadwell-U is coming in spring 2015
At the Intel investor meeting, Intel put up a slide stating that it will launch its Broadwell-U processors -- that is, the low-power Core i3, Core i5, and Core i7 processors -- in spring 2015. The general manager of the company's PC Client Group, Kirk Skaugen, was a bit more specific, stating in his presentation that these processors will launch in "early spring."

I take that statement to mean March or early April of 2015.

If Intel really does end up ramping its 15-watt and 28-watt Broadwell-U parts as steeply as Skaugen suggested in his presentation, then I expect that most PC designs will transition to Broadwell from Haswell. In fact, Skaugen highlighted at Intel's developer forum back in 2013 that the Broadwell-U parts are "socket compatible" with the Haswell-U parts, meaning that system vendors could theoretically just swap them in with minimal hassle.

Given that the rest of the PC industry will be moving to these higher-performing and more efficient Broadwell chips, I'd be surprised if Apple wasn't the first, if not one of the first, to adopt them. Perhaps the more important question, then, is whether Apple will do an all-new industrial design or simply refresh the current MacBook Air.

What does the rumor mill have to say?
According to various rumors floating around the Web, Apple is planning to launch a redesigned 12-inch MacBook Air. MacRumors lists some of the widely expected specifications, including a 12-inch display, an "ultra-slim form factor," a Retina Display, an updated trackpad, and even a "fanless design."

As far as I can tell, it seems unlikely that Apple is just going to drop a Broadwell-U into the current MacBook Air industrial design and call it a day.

What does this mean for Apple?
Perhaps the most important part of the Mac story for investors is whether it can continue to gain market share at a good margin structure against the rest of the PC industry. The good news is that an updated MacBook Air could help drive an upgrade cycle, as Apple has a lot of opportunity to make the new model significantly better than the prior one.

The offset, though, is that the Windows PC industry might get a boost from the launch of Windows 10. While Apple tends to have very good customer retention rates -- meaning I expect very few Mac users to switch back to Windows 10 PCs -- I do think that if Windows 10 is meaningfully better than Windows 8.1 was, Apple's share gain story in the Mac could decelerate.