Power Mac G5: История и Технологии Apple

Line of tower computers designed and manufactured by Apple

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. It was also the first desktop computer from Apple to use an anodized aluminum 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.

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 3 GHz "within 12 months." This would never come to pass; after three years, the G5 only reached 2.7 GHz before it was replaced by the Intel Xeon based Mac Pro, which debuted with processors running at speeds of up to 3 GHz. During the presentation, Apple also showed Virginia Tech's Mac OS X computer cluster supercomputer (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 2.3 GHz.

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, 300 mm 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 90 nm 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).

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 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). 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 16 GB of Dual Channel DDR2 PC4200 RAM using eight memory slots, with support for ECC memory.

2003 June: Initial release at speeds of Single 1.6, Single 1.8, Dual 2.0 GHz. 2003 November: Dual 1.8 replaces Single 1.8 GHz; price reduction on Single 1.6 GHz. 2004 June: 90 nm Dual 1.8, Dual 2.0 and Dual 2.5 GHz replace all previous models. The 2.5 GHz 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, 600 MHz 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 2.5 GHz → Dual 2.7 GHz (PCI X, LC), Dual 2.0 GHz → Dual 2.3 GHz (PCI X), Dual 1.8 GHz → Dual 2.0 GHz (PCI). Newly introduced features were the 16x dual layer SuperDrives across the line and increased storage, up to 800 GB for the higher end models. The 1.8 GHz 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 2.0 GHz → DC 2.0 GHz, Dual 2.3 GHz → DC 2.3 GHz, Dual 2.7 GHz → Dual DC 2.5 GHz (termed a Quad Power Mac G5, with four CPU execution cores and more reliable liquid cooling), all with DDR2 memory, and PCI Express expansion in place of PCI X. The older PCI X, Dual 2.7 GHz 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.