The Power Mac G5 is a series of personal computers designed, manufactured, and sold by Apple Computer, Inc. from 2003 to 2006 as part of the Power Mac series. When introduced, it was the most powerful computer in Apple's Macintosh lineup, and was marketed by the company as the world's first 64-bit desktop computer.[1] It was also the first desktop computer from Apple to use an anodizedaluminum alloy enclosure, and one of only three computers in Apple's lineup to utilize the PowerPC 970 CPU, the others being the iMac G5 and the Xserve G5.
Three generations of Power Mac G5 were released before it was discontinued as part of the Mac transition to Intel processors, making way for its replacement, the Mac Pro. The Mac Pro retained a variation of the G5's enclosure design for seven more years, making it among the longest-lived designs in Apple's history.[2]
Introduction
Officially launched as part of Steve Jobs' keynote presentation at the Worldwide Developers Conference in June 2003, the Power Mac G5 was introduced with three models, sharing the same physical case, but differing in features and performance. Although somewhat larger than the G4 tower it replaced, the necessity for a complex cooling system meant that the G5 tower had room inside for only one optical drive and two hard drives.
Steve Jobs stated during his keynote presentation that the Power Mac G5 would reach 3GHz "within 12 months." This would never come to pass; after three years, the G5 only reached 2.7GHz before it was replaced by the Intel Xeon-based Mac Pro, which debuted with processors running at speeds of up to 3GHz.
During the presentation, Apple also showed Virginia Tech's Mac OS Xcomputer clustersupercomputer (a.k.a. supercluster) known as System X, consisting of 1,100 Power Mac G5 towers operating as processing nodes. The supercomputer managed to become one of the top five supercomputers that year. The computer was soon dismantled and replaced with a new cluster made of an equal number of Xserve G5 rack-mounted servers, which also used the G5 chip running at 2.3GHz.
PowerPC G5 and the IBM partnership
The inside of a Power Mac G5, late 2005 modelThe inside of an air-cooled dual-processor 2003 model
The PowerPC G5 (called the PowerPC 970 by its manufacturer, IBM) is based upon IBM's 64-bit POWER4 microprocessor. At the Power Mac G5's introduction, 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 US$3 billion in a new lab to produce these large, 300mm wafers." This completely automated facility in East Fishkill, New York figured heavily in IBM's larger microelectronics strategy.
The original PowerPC 970 had 50 million transistors and was manufactured using IBM CMOS 9S at 130 nm fabrication process. CMOS 9S is the combination of SOI, low-k dielectric insulation, and copper interconnect technology, which were invented at IBM research in the mid-1990s. 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 Power Mac G5 Quad (for dual-socket, four-core configurations).
Architecture
The PowerPC 970FX inside a PowerMac G5.
The Power Mac G5 line in 2006 consisted of three, dual-core PowerPC G5 configurations, which can communicate through its HyperTransport 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 20GB/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).
All modern 32-bit x86 processors since the Pentium Pro have the Physical Address Extension (PAE) feature, which permits them to use a 36-bit physical memory address to address a maximum of 236 bytes (64 gigabytes) of physical memory, while the PowerPC 970 processor is capable of addressing 242 bytes (4 terabytes) of physical memory and 264 bytes (16 exabytes) of virtual memory. Due to its 64-bit processor (and 42-bit MMU), the final revision of the Power Mac G5 can hold 16GB of Dual-Channel DDR2 PC4200 RAM using eight memory slots, with support for ECC memory.
Product revision history
2003 June: Initial release at speeds of Single 1.6, Single 1.8, Dual 2.0GHz.
2003 November: Dual 1.8 replaces Single 1.8GHz; price reduction on Single 1.6GHz.
2004 June: 90nm Dual 1.8, Dual 2.0 and Dual 2.5GHz replace all previous models. The 2.5GHz model is notable as the first major PC with liquid cooling included as stock.
2004 October: A new Single 1.8 reintroduced, with a slower, 600MHz HyperTransport, 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: Dual 2.5GHz → Dual 2.7GHz (PCI-X, LC), Dual 2.0GHz → Dual 2.3GHz (PCI-X), Dual 1.8GHz → Dual 2.0GHz (PCI). Newly introduced features were the 16x dual-layer SuperDrives across the line and increased storage, up to 800GB for the higher-end models. The 1.8GHz Single was not modified.
2005 June–July: The Single 1.8 model was discontinued in the United States and Europe.
2005 October: Shift to dual-core processors: Dual 2.0GHz → DC 2.0GHz, Dual 2.3GHz → DC 2.3GHz, Dual 2.7GHz → Dual DC 2.5GHz (termed a Quad Power Mac G5, with four CPU execution cores and more reliable[citation needed]liquid cooling), all with DDR2 memory, and PCI Express expansion in place of PCI-X.[3][4][5] The older PCI-X, Dual 2.7GHz model remained available for a while, but the slower speed single-core models were discontinued immediately.
2006 August: The Power Mac is replaced by its Intel successor, the Mac Pro.
Early versions of dual processor G5 computers have noise problems. The first one is ground loop-based interference,[13] which sometimes causes noise leaks into the analog audio outputs. This bug was fixed in Rev. B G5.
The second noise problem came from the 'chirping' sound, which can be triggered by fluctuations in power draw. For example, using Exposé causes a brief chirp.[14] A widely circulated work-around is to disable the CPUs' "nap" feature using Apple's CHUD Tools, but this was not recommended by Apple. This noise problem was not fixed until the dual core generation of G5s was produced, however it did not affect the "Late 2004" model (at least there have never been any reports). The power draw fluctuation was later attributed to the lack of power management features in the single-core processors.[15] Apple eventually posted the chirping bug information on its support site.[16]
Although the noise problems did not prevent the affected computers from working, they were problematic for audio professionals and enthusiasts, especially for the liquid-cooled models, which had been expressly designed as mechanically quiet for discerning listeners.
A common problem among single processor G5s was the cyclic expansion and contraction of a metal plate soldered to the Logic Board connecting all eight of the RAM slots. Eventually, this can cause the computer to no longer detect the RAM, and refuse to boot. Fixes for this include having the plate re-soldered, or exposing the other side of the Logic Board to heat from a heat gun. The latter option is far easier, since it requires neither soldering nor the removal of the Logic Board from the computer.
All 2.5GHz and 2.7GHz dual processor models and the 2.5GHz quad-processor model had a liquid cooling system that consisted of a radiator, coolant pump, and heat exchangers bolted to the processors. The cooling system was made by Delphi Automotive, a former Harrison Radiator Division of General Motors. This was a bold step for Apple, and should have allowed the use of very fast processors, giving Apple an advantage in both performance and reliability, but the system turned out to be subject to coolant leakage, made worse by the system's use of GM Dexcool coolant, which is more corrosive than regular automotive coolant.[17] If not caught in time, the leakage could destroy the processors, logic board, and even corrode the aluminum casing itself. While leakage was sometimes detectable by drops of green coolant in or beneath the machine, in many [vague] machines the seepage is so slight that it was almost impossible to detect without dismantling the entire computer. Later models (only the 2.7GHz) were equipped with a Panasonic liquid cooling system which was much more reliable.[17]
The liquid cooling system fits into the case where the heat sinks would normally go, so there is no easy way to distinguish the liquid-cooled versions from the air-cooled, although most, but not all,[vague] of the liquid-cooled machines have a sticker inside warning about the possibility of leakage. [citation needed]
P.A. Semi's G5 derivative
When P.A. Semi announced the preliminary pre-production plan of PWRficient processor,[18] there had been persistent rumors that Apple would prepare for its use in its professional line of personal computers.[19]
In 2006, The Register reported that P.A. Semi had formed a tight relationship with Apple, which would result in P.A. Semi promptly delivering processor chips for Apple's personal computer notebook line and possibly desktops.[20] Even in 2006, Apple did not have a laptop version of the G5 processor. The processor that would run the personal computers was P.A. Semi's preliminarily proposed processor, PWRficient 1682M (PA6T-1682M). The version that would be sampled for pre-production at third quarter of 2006 was a 2GHz, dual-core CPU with two DDR2 memory controllers, 2MB of L2 cache, and support for 8 PCI Express lanes. The sampled chip also has lower heat intensity than Intel's Core Duo, which gives off 9–31 W under normal load.
According to The Register article, P.A. Semi executives believed that they were all but assured of winning Apple's contract, and CEO Dan Dobberpuhl thought that Apple's hints of moving to Intel were just a persuading tactic. At the time, the companies were working for PWRficient software.
Despite the advantages of more compatible architecture, Apple moved to the Intel architecture officially for 'performance-per-watt' reasons. However, P.A. Semi would not be able to ship its low-power multicore product in volume until 2007, which, combined with P.A. Semi's status as a start-up company, seems to have been the final blow to the development of Power Mac computers. However, it was also speculated that Apple switched to Intel processor because Apple could no longer abide the constant delays in performance ramp up,[21] desired native Windows compatibility, or it was Apple's strategy to shift its business focus away from desktop computing to iPod (and subsequently iOS) development.
↑ Gwennap, Linley; Bob Wheeler; Jag Bolaria; Joseph Byrne (November 10, 2005). "The Linley Group". The Linley Wire. The Linley Group. Archived from the original on August 19, 2008. Retrieved June 27, 2008.
PowerPC is a reduced instruction set computer (RISC) instruction set architecture (ISA) created by the 1991 Apple–IBM–Motorola alliance, known as AIM. PowerPC, as an evolving instruction set, has been named Power ISA since 2006, while the old name lives on as a trademark for some implementations of Power Architecture–based processors.
The Power Macintosh, later Power Mac, is a family of personal computers designed, manufactured, and sold by Apple Computer, Inc as the core of the Macintosh brand from March 1994 until August 2006.
HyperTransport (HT), formerly known as Lightning Data Transport, is a technology for interconnection of computer processors. It is a bidirectional serial/parallel high-bandwidth, low-latency point-to-point link that was introduced on April 2, 2001. The HyperTransport Consortium is in charge of promoting and developing HyperTransport technology.
Xeon is a brand of x86 microprocessors designed, manufactured, and marketed by Intel, targeted at the non-consumer workstation, server, and embedded markets. It was introduced in June 1998. Xeon processors are based on the same architecture as regular desktop-grade CPUs, but have advanced features such as support for error correction code (ECC) memory, higher core counts, more PCI Express lanes, support for larger amounts of RAM, larger cache memory and extra provision for enterprise-grade reliability, availability and serviceability (RAS) features responsible for handling hardware exceptions through the Machine Check Architecture (MCA). They are often capable of safely continuing execution where a normal processor cannot due to these extra RAS features, depending on the type and severity of the machine-check exception (MCE). Some also support multi-socket systems with two, four, or eight sockets through use of the Ultra Path Interconnect (UPI) bus, which replaced the older QuickPath Interconnect (QPI) bus.
The Xserve was a series of rack-mounted servers manufactured by Apple Inc. between 2002 and 2011. It was Apple's first rack-mounted server, and could function as a file server, web server or run high-performance computing applications in clusters – a dedicated cluster Xserve, the Xserve Cluster Node, without a video card and optical drives was also available. The first Xserve had a PowerPC G4 processor, replaced by a PowerPC G5 in 2004, and by Intel Xeon processors in 2006; each was available in single-processor and dual-processor configurations. The Xserve was discontinued in 2011, and replaced with the Mac Pro Server and the Mac Mini Server.
The PowerPC 970, PowerPC 970FX, and PowerPC 970MP are 64-bit PowerPC CPUs from IBM introduced in 2002. Apple branded the 970 as PowerPC G5 for its Power Mac G5.
In computing, a northbridge is one of two chips comprising the core logic chipset architecture on motherboards for older personal computers. A northbridge is connected directly to a CPU via the front-side bus (FSB) to handle high-performance tasks, and is usually used in conjunction with a slower southbridge to manage communication between the CPU and other parts of the motherboard.
PowerPC G4 is a designation formerly used by Apple and Eyetech to describe a fourth generation of 32-bit PowerPC microprocessors. Apple has applied this name to various processor models from Freescale, a former part of Motorola. Motorola and Freescale's proper name of this family of processors is PowerPC 74xx.
The Power Mac G4 is a series of personal computers designed, manufactured, and sold by Apple Computer from 1999 to 2004 as part of the Power Macintosh line. Built around the PowerPC G4 series of microprocessors, the Power Mac G4 was marketed by Apple as the first "personal supercomputers", reaching speeds of 4 to 20 gigaFLOPS. This was the first existing Macintosh product to be officially shortened as "Mac", and is the last Mac able to boot into classic Mac OS.
The iMac G5 is an all-in-one personal computer that was designed, manufactured and sold by Apple Computer from August 2004 to March 2006. It is the final iMac to use a PowerPC processor, making it the last model that could natively run Mac OS 9 (Classic) applications.
The Mac transition to Intel processors was the process of switching the central processing units (CPUs) of Apple Inc.'s line of Mac and Xserve computers from PowerPC processors over to Intel's x86-64 processors. The change was announced at the 2005 Worldwide Developers Conference (WWDC) by then-Apple CEO Steve Jobs, who said Apple would gradually stop using PowerPC microprocessors supplied by Freescale and IBM.
The megahertz myth, or in more recent cases the gigahertz myth, refers to the misconception of only using clock rate to compare the performance of different microprocessors. While clock rates are a valid way of comparing the performance of different speeds of the same model and type of processor, other factors such as an amount of execution units, pipeline depth, cache hierarchy, branch prediction, and instruction sets can greatly affect the performance when considering different processors. For example, one processor may take two clock cycles to add two numbers and another clock cycle to multiply by a third number, whereas another processor may do the same calculation in two clock cycles. Comparisons between different types of processors are difficult because performance varies depending on the type of task. A benchmark is a more thorough way of measuring and comparing computer performance.
A multi-core processor is a microprocessor on a single integrated circuit with two or more separate processing units, called cores, each of which reads and executes program instructions. The instructions are ordinary CPU instructions but the single processor can run instructions on separate cores at the same time, increasing overall speed for programs that support multithreading or other parallel computing techniques. Manufacturers typically integrate the cores onto a single integrated circuit die or onto multiple dies in a single chip package. The microprocessors currently used in almost all personal computers are multi-core.
Mac Pro is a series of workstations and servers for professionals made by Apple Inc. since 2006. The Mac Pro, by some performance benchmarks, is the most powerful computer that Apple offers. It is one of four desktop computers in the current Mac lineup, sitting above the Mac Mini, iMac and Mac Studio.
Microprocessors belonging to the PowerPC/Power ISA architecture family have been used in numerous applications.
Skulltrail is an enthusiast gaming platform released by Intel on February 19, 2008. It is based on Intel's 5400 "Seaburg" workstation chipset. The primary difference between Skulltrail and Intel's current and past enthusiast chipsets is a dual CPU socket design that allows two processors to operate on the same motherboard. Therefore, Skulltrail can operate eight processing cores on one system. The platform supports two Core 2 Extreme QX9775 processors, which operate at 3.2 GHz.
The iMac is a line of all-in-one Mac desktop computers designed and built by Apple Inc. It has been the primary part of Apple's consumer desktop offerings since its debut in August 1998, and has evolved through seven distinct forms.
The Mac transition to Apple silicon was the process of switching the central processing units (CPUs) of Apple Inc.'s line of Mac computers from Intel's x86-64 processors to Apple-designed systems on a chip that use the ARM64 architecture.
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