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Power Mac G5The Power Mac G5 is Apple Computer's name for models of the Power Mac which utilize the PowerPC G5 processor. Introduction The current revision of the Power Mac G5 comes in three dual-processor models with dual-1.8, dual-2.0 and dual-2.5 GHz PowerPC G5 processors, and one single 1.8GHz PowerPC G5 processor model. The price points of these computers range from $1499 (USD) on the low end to $2999 (USD) on the high end. The G5 can communicate through its frontside bus at up to half its internal clock speed: a 2.5GHz G5 thus has a 1.25GHz FSB. Note, however, that the 1.8GHz single model has a one-third bus (600MHz). Each processor in the 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 PowerMac 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. In addition, due to the 64-bit processor (and therefore 64-bit MMU) the PowerMac G5 has a RAM capacity of eight gigabytes; eight RAM slots, and 1 GB per stick. (A full four gigabytes above current theoretical limits on 32-bit processors, though it should be noted that, despite Apple's eight-gigabyte claim, it can most likely hold sixteen gigabytes, using 2GB RAM sticks. The G5 (PowerPC 970) processor itself is capable of addressing 264 bytes of RAM, or eight exabytes (8 EB). Obviously there aren't RAM modules of anywhere near that density, but the potential alone inspires appreciation in some.) The memory in the PowerMac G5 is the equivalent of Dual-Channel DDR400, but Apple likes to call it "128-bit DDR" instead of Dual-Channel. This means a bandwidth of 6.4 GBps. The large case has room, after installing the mounting plate, for six 500GB internally-powered SATA hard drives for a total inner capacity of 3 TB (3000 GB). Two 500GB external SATA drives bring the G5's total capacity to 5 TB. (see G5Jam) Eleven-hundred Power Mac G5s formed the processing nodes of Virginia Tech's original Mac OS X computer cluster supercomputer (a.k.a. supercluster) known as The Big Mac. The computer was soon dismantled and replaced with a new cluster made of an equal number of Apple's Xserve rack-mounted servers, which also use the G5 chip running at 2.3 GHz. PowerPC G5 processor The PowerPC G5 (called the PowerPC 970FX by its manufacturer, IBM) is based upon IBM's Power4 processor architecture. 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 dollars in a new lab to produce these large, 300-millimetre 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 PowerPC G5 microprocessor has over 58 million transistors on it and it incorporates IBM's 90-nanometre (.09-micrometre) fabrication process. That's 1/1000th the diameter of a human hair. The processor is manufactured with SOI technology, and IBM's additive-copper, dual-damascene wiring process allows for copper to be used in chip wiring. Also, IBM has already built the POWER5, which is rumored to be the basis for the next generation of PowerPC processors. The Power5 has multiple improvements over the POWER4 which includes IBM's version of simultaneous multithreading (the Intel version is HyperThreading), and advanced power management features. Due to the dual-core nature of the Power 5 and its inclusion of Simultaneous Multithreading, each CPU Core appears to be comprised of 4 CPUs. Other improvements include a dedicated single-tasking mode. 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 2.0GHz
- 2003 November: DP 1.8 replaces SP 1.8GHz; a price reduction on SP 1.6GHz
- 2004 June: 90nm DP 1.8, DP 2.0 and liquid-cooled DP 2.5GHz replace all previous models
- 2004 October: A new SP 1.8 reintroduced, with a slower, 600MHz FSB (Frontside Bus), likely based upon the iMac G5's architecture
A partial list of official firmware updates References External links
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