The Mac transition to Apple silicon was the process of changing the central processing units (CPUs) of Apple Inc.'s line of Mac computers from Intel's x86-64 processors to Apple-designed systems on a chip that use the ARM64 architecture.
Apple CEO Tim Cook announced a "two-year transition plan" to Apple silicon on June 22, 2020. The first Macs with Apple-designed systems on a chip were released that November; the last, the Mac Pro, was released in June 2023, completing the transition in three years.
The transition was the third time Apple had switched the Macintosh to a new instruction set architecture. The first was from the Motorola 68000 series to PowerPC chips in 1994, and the second was from PowerPC to Intel processors using the x86 architecture in 2005–2006.
Background
The first Macintoshes, introduced in 1984, were based on the Motorola 68000 architecture. In the early 1990s, Apple evaluated several possibilities, then switched to the PowerPC family it co-developed with IBM and Motorola. It switched again, starting in 2005, to Intel 32-bit and 64-bit x86. In 2011, Mac OS X Lion dropped support for Macs with 32-bit processors; in 2019, macOS Catalina dropped support for 32-bit Intel apps. Supported 64-bit Intel systems can still boot the latest versions of macOS.
The genesis of the third switch began in 1985, when Acorn's ARM architecture was spotted by Apple's Advanced Technology Group, an internal research laboratory. The ATG thought it might replace the MOS 6502 of the Apple II range or the 68000 of the original Macintosh, or become the basis of a tablet device, under Paul Gavarini and Tom Pittard, in a project labelled Möbius. A partnership was established with Acorn Computers, and VLSI in 1990, and work began on a chip for small devices. The first Apple products with an ARM system on a chip were the 1993 Newton personal digital assistant, the 2001 iPod, and the 2007 iPhone. Apple has designed its own custom ARM chips since 2009, which it has since used in its iPhone, iPad, iPod, Apple TV, Apple Watch, AirPods, Beats, AirPort Time Capsule and HomePod products. Between October 2016 and August 2020, Intel-based Macs with Apple-designed ARM co-processors were released.
In the 2010s, media reports documented Apple's frustrations and challenges with the pace and quality of Intel's technology development. Apple reportedly had trouble with Intel modems for iPhones in 2017 due to technical issues and missed deadlines. Meanwhile, a 2018 report suggested that Intel chip issues prompted a redesign of the MacBook. In 2019, Apple blamed Intel processor shortages for a decline in Mac sales. In June 2020, former Intel principal engineer François Piednoël said Intel's "abnormally bad" quality assurance in its Skylake processors, making Apple "the number one filer of problems in the architecture", helped Apple decide to migrate. Intel CTO Mike Mayberry countered that quality assurance problems may arise at large scale from any CPU vendor.
History
Early involvement with ARM
In 1983, Acorn Computers started working on a project to design its own CPU architecture and instructions set, called the Acorn RISC Machine (ARM). In 1985, Apple's Advanced Technology Group worked with Acorn to create an experimental prototype, code-named Mobius, to replace the Apple II, using a modified ARM processor. The project was cancelled but Apple again partnered with Acorn when it needed a low-power, efficient processor for its future Newton PDA. In 1990, a new joint-venture was created between Acorn, Apple and VLSI Technology with the goal of pursuing the development of the ARM processor. The company was named Advanced RISC Machines Ltd, becoming the new meaning of the ARM acronym. One of the first designs of the new company would be the ARM610 SoC, initially for Apple, that allowed the Endianness to be swapped, increased the address space from 26 bit (64 MB) to 32 bit (4 GB), and modified the memory management unit. Apple held a 43% stake in the company, which was reduced to 14.8% in 1999.
Switch from PowerPC to Intel
In 2005 and 2006, Apple moved its Macintosh computers from IBM's PowerPC CPUs to Intel's x86 CPU architecture. At his 2005 WWDC keynote address, Steve Jobs said that continuing to use PowerPC processors, which consumed more energy than Intel chips, would prevent Apple from making better workstation computers and laptops. "As we look ahead, we can envision some amazing products we want to build...And we don't know how to build them with the future PowerPC roadmap", Jobs said.