Power Mac G5

The Power Mac G5 is Apple Computer's name for models of the Power Mac which contain the PowerPC G5 CPU. The professional-grade computer was unarguably the most powerful in Apple's lineup when it was introduced, and was touted by Apple as the fastest personal computer ever built.^*^* It was officially launched at the 2003 WWDC.

Introduction

The current revision of the Power Mac G5 is available in three, dual-core PowerPC G5 configurations, operating at 2.0, 2.3, and a dual-processor 2.5 GHz configuration (the dual contains four cores in total, two per processor). The G5 processor is a common name given to several different chips manufactured by IBM: the PowerPC 970, 970FX, and 970MP, based upon IBM’s POWER4 processor. Prices range from States dollar|US$" target="_blank" >^*1,999 for the dual-core 2.0 GHz configuration to US$3,299 for a quad-core 2.5 GHz configuration. The older, single-core, dual-processor 2.7 GHz model is still available. It contains PCI-X slots, where the newer models use PCI Express. The dual-core G5 configuration can communicate through its FSB at half its internal clock speed. Each processor in the Power Mac G5 has two unidirectional 32-bit pathways: one leading to the processor and the other from the processor. These result in a total bandwidth of up to 20 GB/s. The processor at the heart of the Power Mac G5 has a "superscalar, superpipelined" execution core that can handle up to 216 in-flight instructions, and uses a 128-bit, 162-instruction SIMD unit (AltiVec).

In addition, due to the 64-bit processor (and 42-bit MMU) the Power Mac G5 has a RAM capacity greater than the four gigabyte addressable memory limit of traditional 32-bit processors. Currently, the Power Mac G5 can hold sixteen gigabytes of RAM using eight memory slots with 2 GB per stick, a full twelve gigabytes above current limits on 32-bit processors (assuming there is no 36-bit memory address unit, included in all modern CPUs, which allows the processor to address more than 4 GB RAM, but with a performance hit). The Power Mac G5's PowerPC 970 processor itself is capable of addressing 2⁴² bytes (4 terabytes) of physical RAM and 2⁶⁴ bytes (8 exabytes) of Virtual RAM. There are no RAM modules of that density, but the potential alone inspires appreciation in some. The memory in the Power Mac G5 is Dual-Channel DDR2 PC4200, with support for ECC memory.

1100 Power Mac G5s formed the processing nodes of Virginia Tech's original Mac OS X computer cluster supercomputer (a.k.a. supercluster) known as System X, which managed to become one of the top 10 supercomputers. The computer was soon dismantled and replaced with a new cluster made of an equal number of Xserve G5 rack-mounted servers, which also use the G5 chip running at 2.3 GHz.

In 2003 Steve Jobs promised that the Power Mac G5 would reach 3 GHz one year after it was announced. However, to date the G5 has only reached 2.7 GHz (or dual-core at 2.5 GHz). With Apple's announcement that it will transition its system from IBM-based to Intel-based processors, it is expected that the Power Mac model will be Intel-based by the end of 2006. ^*

PowerPC G5 processor

The PowerPC G5 (called the PowerPC 970 by its manufacturer, IBM) is based upon IBM's dual-core POWER4 microprocessor. At the introduction of the Power Mac G5, Apple announced a partnership with IBM in which IBM would continue to produce PowerPC variants of their POWER processors. According to IBM's Dr. John E. Kelly, "The goal of this partnership is for Apple and IBM to come together so that Apple customers get the best of both worlds, the tremendous creativity from the Apple corporation and the tremendous technology from the IBM corporation. IBM invested over $3 billion US dollars in a new lab to produce these large, 300 mm wafers." (This lab is a completely automated facility located in East Fishkill, New York, and figures heavily in IBM's microelectronics strategy above and beyond the partnership with Apple). The original PowerPC 970 has 58 million transistors and is manufactured using IBM CMOS 9S at 130 nm fabrication process. (One hundred thirty nanometers, or 130 billionths of a meter, is approximately one thousandth the diameter of a human hair). CMOS 9S is the combination of SOI, Low-k dielectric insulation, and Copper interconnect technology, which were invented at IBM research in the mid-90's. Subsequent revisions of the "G5" processor have included IBM's PowerPC 970FX (same basic design on a 90nm process), and the PowerPC 970MP (essentially two 970FX cores on one die). Apple refers to the dual-core PowerPC 970MP processors as either the "G5 Dual" (for single socket, dual-core configurations), or "G5 Quad" (for dual socket, four-core configurations).

Product revision history

(Note: DP designates a Dual-Processor machine, and SP designates a Single-Processor machine)

2003 June: Initial release at speeds of SP 1.6, SP 1.8, DP 2.0 GHz
2003 November: DP 1.8 replaces SP 1.8 GHz; a price reduction on SP 1.6 GHz
2004 June: 90 nm DP 1.8, DP 2.0 and liquid-cooled DP 2.5 GHz replace all previous models
2004 October: A new SP 1.8 reintroduced, with a slower, 600 MHz FSB (Frontside Bus), PCI bus, based upon the iMac G5's architecture (U3lite and Shasta chips). Apple's official name for this machine is "Power Mac G5 (Late 2004)".
2005 April: CPU speed increased: DP 2.5 GHz → DP 2.7 GHz (PCI-X), DP 2.0GHz → DP 2.3 GHz (PCI-X), DP 1.8 GHz → DP 2 GHz (PCI). Newly introduced features were the 16x Double-Layer SuperDrives across the line and increased storage, up to 800 GB for the higher-end models. The 1.8 GHz SP was not modified.
2005 June: The SP 1.8 model was discontinued in the U.S.
2005 July: And also in Europe
2005 October: Shift to Dual-core processors: DP 2.0 GHz → DC 2.0 GHz, DP 2.3 GHz → DC 2.3 GHz, DP 2.7 GHz → DP DC 2.5 GHz (termed a Quad Power Mac G5, with four CPU execution cores), all with DDR2 memory, and PCI Express expansion in place of PCI-X. The older PCI-X, DP 2.7 GHz model remained available for a while, but the slower speed single-core models were discontinued immediately.

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Introduction

PowerPC G5 processor

Product revision history

A partial list of official firmware updates

References

External links