PowerPC to Intel Transition
From Mac Guides
At the Worldwide Developers Conference 2005, Apple announced that it would phase out PowerPC processors in favor of Intel processors on its computer lines. This was the second major processor transition for Apple, the first being the switch from 68k processors to PowerPC processors in the mid-90s.
According to Steve Jobs, "We wanna be making the best computers for our customers looking forward." As Apple looked at the future roadmaps, Jobs stated that while they can envision some amazing products in the future, they don't know how to build them with future PowerPC chips. Meanwhile, when Apple was looking at Intel's future roadmap for both performance and power, they found that Intel had a much better "Performance per Watt" ratio.
Timeline of Transition
At the WWDC Conference, Jobs announced that the transition will be a gradual one, over the course of one year. At the time, Jobs announced that the transition shall be complete by the end of 2007.
The transition officially began at Macworld San Francisco in January 2006, where the professional PowerBook laptop line and consumer iMac desktop line transitioned over to Intel Core Duo processors. At the same time, the name "Power" in "PowerBook", which was widely believed to be a name associated with its processors, was changed to MacBook Pro. This also started a naming custom of having the word "Mac" across the Apple line.
The first wave of transition was followed in February 28, 2006 with the transitioning of the Mac Mini line, and on May 16th, 2006, where the iBook consumer laptop line transitioned over and renamed MacBook.
The transition took place over the course of one year, and was completed more than one year ahead of schedule.
Due to the different programming codes used on PowerPC and intel processors, changing processors on Mac computers would also require a complete rewrite of all Mac softwares, including the operating system, to accommodate the change.
At WWDC 2005, Jobs revealed that since Mac OS X was being developed, it was compiled to run natively on both PowerPC and Intel codes. As a result, Mac OS X will not require any code rewrites for deployment in Intel Macs.
Mac also began to use the term "Universal Binary" (commonly known as "Universal") on any softwares that accommodates both PowerPC and Intel Macs. by 2007, Apple's website has listed more than 6,000 applications that are Universal.
In an effort to ease the inevitable inconveniences that comes with changes of such a major scale, Apple developed a background dynamic translator called Rosetta to emulate a PowerPC environment on Intel Macs. This layer translates G3, G4, and Velocity Engine instructions. G5 instructions, as well as Mac OS (Classic Environment) instructions were not supported.
Features described at the WWDC included:
- Dynamic binary translation
- Runs existing apps
- Transparent to users
- Sufficient speed for meaningful use (for most softwares)
Advantages of Transition
- Better performance with lower power consumption, which is considered crucial for laptops.
- Faster chips, especially for laptops.
- Dual-boot (having two OSes-Mac OS X and another OS- within a Mac) abilities without performance penalties. This potential was realized with Boot Camp, which allows any Mac users to run Windows on an Intel Mac without the need for Virtual PC.