This isn’t as crazy as it seems: Apple’s been designing its own System-on-Chip (SoC) for the iPhone since March 2010 and in its most recent executive shakeup, the press release placed Bob Mansfield in charge of “Technologies” and said that his semiconductor teams have “ambitious plans for the future.” Plus, there are perpetual rumors that Apple’s got a MacBook somewhere in Cupertino running on an ARM processor. If the Mac platform ever moved away from Intel processors, it would be a big blow to the American semiconductor giant. On the other hand, there are numerous issues that this could cause for Apple’s normally stable-and-simple OS X: a decrease in performance, drivers that suddenly don’t work, and software rendered obsolete.
It’s probably safe to assume that Apple is in fact testing out Macs with ARM processors, but it won’t happen for a while.