PowerPC (an acronym for Performance Optimization With Enhanced RISC – Performance Computing, sometimes abbreviated as PPC) is a RISC instruction set architecture created by the 1991 Apple–IBM–Motorola alliance, known as AIM. PowerPC, as an evolving instruction set, has since 2006 been named Power ISA, while the old name naturally lives on, as a legacy trademark for some implementations of Power Architecture based processors, and in software package identifiers.

Originally intended for personal computers, PowerPC CPUs have since become popular as embedded and high-performance processors. PowerPC was the cornerstone of AIM's PReP and Common Hardware Reference Platform initiatives in the 1990s and while the architecture is well known for being used by Apple's Power Macintosh, PowerBook, iMac, iBook, and Xserve lines from 1994 to 2006 (before Apple's transition to Intel), its use in video game consoles and embedded applications provided an array of uses. In addition, PowerPC CPUs are still used in AmigaOne and third party AmigaOS 4 personal computers.

PowerPC G4 is a designation used by Apple Computer and Eyetech to describe a fourth generation of 32-bit PowerPC microprocessors. Apple has applied this name to various (though closely related) processor models from Freescale, a former part of Motorola. Motorola and Freescale's proper name of this family of processors is PowerPC 74xx.

Macintosh computers such as the PowerBook G4 and iBook G4 laptops and the Power Mac G4 and Power Mac G4 Cube desktops all took their name from the processor. PowerPC G4 processors were also used in the eMac, first-generation Xserves, first-generation Mac Minis, and the iMac G4 before the introduction of the PowerPC 970.

Apple completely phased out the G4 series for desktop models after it selected the 64-bit IBM-produced PowerPC 970 processor as the basis for its PowerPC G5 series. The last desktop model that used the G4 was the Mac Mini which now comes with an Intel processor. The last portable to use the G4 was the iBook G4 but was replaced by the Intel-based MacBook. The PowerBook G4 has been replaced by the Intel-based MacBook Pro.

The PowerPC 600 family was the first family of PowerPC processors built. They were designed at the Somerset facility in Austin, Texas, jointly funded and staffed by engineers from IBM and Motorola as a part of the AIM alliance. Somerset was opened in 1992 and its goal was to make the first PowerPC processor and then keep designing general purpose PowerPC processors for personal computers. The first incarnation became the PowerPC 601 in 1993, and the second generation soon followed with the PowerPC 603, PowerPC 604 and the 64-bit PowerPC 620.

Nuclear family

PowerPC 601