Next-Generation PowerPC
Architecture
The PowerPC G5 is a highly parallel implementation of the PowerPC architecture,
capable of handling multiple assorted tasks at the same time. It’s based on the execu-
tion core of IBM’s 64-bit POWER4 processor—recipient of the Microprocessor Report’s
2001 Analyst’s Choice Award for Best Workstation/Server Processor, which recognizes
excellence in semiconductor technology innovation, design, and implementation.
With two double-precision floating-point units, advanced branch prediction logic,
and a high-bandwidth frontside bus, the POWER4 drives IBM’s top-of-the-line pSeries
690 servers.
Apple collaborated with IBM to leverage this industry-leading design for the next
generation of personal computing. The development of the PowerPC G5 builds on
previous PowerPC designs, combining an optimized Velocity Engine with a superscalar,
superpipelined execution core that supports up to 215 simultaneous in-flight instruc-
tions. And all this power is fabricated in IBM’s state-of-the-art 130-nanometer process
technology using high-performance silicon-on-insulator (SOI) transistors and copper
interconnects.
Ultrafast Access to Data and Instructions
The PowerPC G5 features processing innovations that optimize the flow of data
and instructions—making it ideal for media streaming, HD video editing, real-time
effects, audio synthesis, image processing, 3D rendering, numerical analysis, and
physical modeling.
It starts with 512K of L2 cache that provides the execution core with ultrafast access to
data and instructions—up to 32 GBps. Instructions are prefetched from the L2 cache
into a large, direct-mapped 64K L1 cache at up to 64 GBps. As they are accessed from
the L1 cache, up to eight instructions are fetched per clock cycle. Next, instructions are
decoded and divided into smaller, faster-executing operations. In addition, 32K of L1
data cache can prefetch up to eight active data streams simultaneously.
This efficient preparation maximizes processing speed as instructions are dispatched
into the execution core and data is loaded into the registers.
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White Paper
PowerPC G5
The PowerPC G5 is fabricated using state-of-
the-art 130-nanometer circuitry with more
than 1130 feet of ultrathin wiring—nearly
800 times thinner than a human hair.
