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Does it rock? Or does it suck? (You know it rocks!) – MikeTrent

PowerPC is a 32- and 64-bit RISC microprocessor architecture originally developed by the AIM alliance (a partnership between Apple, IBM, and Motorola) in 1991.

The first PowerPC implementation was the 32-bit 601, released in 1992. The 601 was a transitional design, based on IBM’s existing work on a single-chip POWER processor and Motorola’s m88k bus architecture, and as such, it deviated slightly from the PowerPC architecture (for example, it had no Time Base or DBAT registers).

The first processors to fully implement the 32-bit subset of the PowerPC architecture were the 603 (Motorola) and 604 (IBM) series. Next came the 750 series (74x,75x - known in Apple parlance as the GeeThree). Motorola improved the 750 design, adding the AltiVec unit, to produce the 74xx or GeeFour series (7400/7410/744x/745x).

The first implementation of the original 64-bit architecture was the 620, which was essentially a 64-bit 604. It was produced, but only after so many delays that it was superceeded by the next generation of PowerPC chips soon after its release. IBM may have used it in some of its servers.

Another interesting PowerPC processor is the 64-bit 970, produced by IBM, which is a redesigned single-core POWER4 with an AltiVec unit attached. This chip is used in Apple’s PowerMac GeeFive. The 970FX is a faster, lower power version of the 970. The 970MP is a dual-core version of the 970.

There are, of course, many other PowerPCs than the ones used in Macs. The Xbox360 will use a custom PowerPC processor. The PlayStation3 will use the POWER3-derived Cell processor. Motorola (now FreeScale) has a wide array of processors targeted at the embedded systems market. IBM produces processors for the embedded systems and server markets (the POWER4, for instance, jumps immediately to mind). These other processors are compatible with the original PowerPC architecture to varying degrees: many of the embedded processors implement the BookE architecture, and many of IBM’s processors implement the POWER3/4/5 architectures.


The PowerPC Architecture, 2nd Edition, A Specification for a New Family of RISC Processors. Defines the original 3 “books” of the PowerPC architecture. It is available from the IBM Publications Center for $0.95 in hard-cover (SA14-2083-00) and soft-cover (SA14-2082-00).

Programming Environments Manual For 32-Bit Implementations of the PowerPC Architecture

“The PowerPC Compiler Writer’s Guide (July 23, 2003)”

External Links

Wikipedia: PowerPC - Wikipedia: IBM POWER - Freescale PowerPC Processors - IBM Power Architecture Technology -