Start64!More than a year ago, a crescendo of rumors talked up the idea that Apple would shift the Mac platform to its ARM-based A-series processors. This idea appeared to go into hibernation, but with last week's release of the iPhone 5s and its 64-bit A7 processor, the rumor has gained traction.

Many are impressed with the continuing results of Apple's microprocessor division following its buyout of P.A. Semiconductor in 2008. However, Apple has long produced a variety of ASICs and cores, including various bridge chips and during the PowerPC days in the 1990s, the floating-point instruction set called AltiVec, VMX, or the Velocity Engine. AltiVec was used in P.A. Semiconductor's PWRficient processors.