PowerPC 604

PowerPC 604
Name	PowerPC 604
Produced	1994–1997
Slowest	120
Fastest	225
Design	PowerPC
Arch	PowerPC

PowerPC 604 The PowerPC 604 was a microprocessor family introduced in 1994 that targeted workstations, servers, and high-end personal computers. It emerged from collaborations among IBM, Motorola, and Apple Inc. and competed with processors from Intel Corporation, Sun Microsystems, and Hewlett-Packard. The design influenced later processors used in products from Compaq, SGI, and Apple Computer.

Development and Design

The 604 project began within a partnership involving IBM, Motorola, and Apple Inc. as part of the larger PowerPC initiative that included earlier models like the PowerPC 601 and concepts from the Reduced Instruction Set Computing movement. Key engineering teams from IBM Research, Motorola Semiconductor, and Apple's Power Macintosh division contributed to microarchitecture choices and trade-offs between clock rate and instruction throughput. Corporate strategy debates among executives at IBM, Motorola, Apple Inc., and market analysts at Gartner shaped decisions about fabrication processes at fabs such as IBM Microelectronics and Motorola Fab. The 604's timetable intersected with product launches from Apple Computer and workstation roadmaps at Sun Microsystems and Silicon Graphics.

Architecture and Features

The 604 implemented a superscalar, out-of-order capable design with multiple functional units inspired by concepts from John Cocke's teams at IBM Research and ideas prevalent in architectures like the MIPS R4000. It featured separate integer and floating-point pipelines, a load/store model consistent with earlier PowerPC implementations seen at Apple Computer's Power Macintosh product line, and extensive branch prediction techniques similar to those explored at DEC and Intel Corporation. The core incorporated a unified L1 cache hierarchy and options for external L2 cache as used by systems from Compaq and SGI, while instruction set compatibility aligned with specifications defined by the AIM alliance and standards discussed at conferences like IEEE International Solid-State Circuits Conference. Power management and thermal considerations were addressed in collaboration with packaging teams that had worked on products for IBM, Motorola, and Apple Inc..

Variants and Successors

Several derivatives and follow-on designs extended the 604 lineage, with successors developed within IBM's and Motorola's roadmaps that responded to market pressures from Intel Corporation's Pentium Pro and later Pentium II, and from Sun Microsystems' UltraSPARC line. Notable families that succeeded the 604 line included designs evolved by IBM under project names and by Motorola's semiconductor groups, which later fed into products used by Apple Computer and companies like Gateway and Dell Inc.. The evolution reflected broader industry shifts driven by corporate strategies at IBM, acquisitions involving Motorola, and platform transitions at Apple Inc..

Implementations and Uses

Systems using the 604 appeared in high-end desktop and server markets from vendors such as Apple Computer in the Power Macintosh series, IBM in select workstations and entry servers, Silicon Graphics in certain graphics workstations, and OEMs like Compaq and Gateway. The processor was employed in compute-intensive applications in industries serviced by Adobe Systems creative tools, engineering suites from Autodesk, and scientific computing deployments at research institutions like Lawrence Livermore National Laboratory and Los Alamos National Laboratory. Integration into motherboard designs required collaborations with chipset providers and system integrators including teams from IBM, Motorola, and third-party vendors showcased at events like the COMDEX trade show.

Performance and Benchmarks

Benchmarks of the 604 against contemporaries from Intel Corporation, Sun Microsystems, and DEC were reported in industry publications and evaluated by independent labs such as SPEC and reviewers at PC Magazine and Byte (magazine). Performance characteristics highlighted strengths in floating-point workloads favored by users of SGI graphics applications and weaknesses at certain integer tasks compared with Intel's offerings, with results influenced by clock speed, cache configuration, and compiler optimization from toolchains like those developed by GNU Project, Intel, and IBM. Comparative performance analyses were presented at venues including the ACM SIGARCH conference and discussed in whitepapers by firms such as Mercury Research.

Legacy and Impact

The PowerPC 604 contributed to the consolidation of the PowerPC architecture across platforms from Apple Computer, IBM, and workstation vendors, influencing subsequent designs in embedded and server markets and informing processor strategy debates at Apple Inc. that later led to transitions involving Intel Corporation. Its development highlighted partnerships like the AIM alliance and technology transfer among IBM Research, Motorola Semiconductor, and software vendors such as Microsoft for cross-platform support. The 604's architectural choices and market deployment impacted education at institutions like Stanford University and Massachusetts Institute of Technology where microarchitecture research continued, and it remains cited in retrospectives on 1990s computing alongside milestones involving Intel Corporation and Sun Microsystems.

Category:PowerPC processors