What is PowerPC?

PowerPC is a microprocessor architecture, that uses reduced instruction-set computing (RISC). It was developed jointly by Apple, IBM, and Motorola, after having founded the AIM PowerPC Alliance in 1991. The PowerPC chip is used principally in IBM workstations with its UNIX-based operating system, AIX, and in Apple Computer's Macintosh personal computers with their MacOS and MacOS X operating systems. The three developing companies have made the PowerPC architecture an open standard, inviting other companies to build the architecture further.

The PowerPC architecture provides an alternative for any computer maker to the extremely popular processor architectures from Intel, including the Pentium PC architecture, but also to the AMD processors, gaining more and more in popularity.

Developed at IBM, reduced instruction-set computing (RISC) is based on studies showing that the simpler computer instructions are the ones most frequently performed. Traditionally, processors have been designed to accommodate the more complex instructions as well. RISC performs the more complex instructions using combinations of simple instructions. The timing for the processor can then be based on simpler and faster operations, enabling the microprocessor to perform more instructions for a given clock speed. Typically, the PowerPC can perform one instruction for each clock cycle.

The latest PowerPC chips include the 32bit G3/G4 CPUs used in Apple computers and the 64bit Power3/Power4 CPUs used in IBM workstations.