Posted 13 November 2012 - 04:41 PM
If performance and vertical integration for desktop processors were the only issues, Apple would be better off going back to PowerPC. PowerPC has the best performance these days and Apple owns PA Semi, a PowerPC chip maker that they purchased and then retooled them for ARM, so that they could make the A4 chip.
There were two main reasons Apple dropped the PowerPC, one of them never really mentioned. The well known and official reason is that they couldn't get a G5 into a laptop. The G5 was built for grunt, not mobile devices. IBM was well advanced with a mobile G5 when Apple pulled the pin. The other and probably more compelling reason was Windows compatibility. Many people would not buy Mac because it meant putting all of their eggs in one basket, their old Windows software wouldn't work, unless they used VirtualPC. VirtualPC was made by Connectix which had been purchased by guess who? Yep, Microsoft. If Apple were to want a broader market they needed to support people running Windows apps, and now Microsoft owned the key to that market. Supporting Windows natively made a huge amount of sense, much more than changing processors because of performance.
So, if Apple are to change processors in their Mac's, they will need to run Windows, so that means either X86 or ARM. Intel is well ahead of ARM in terms of raw performance, so I can't see them changing processors anytime soon.