Less than a year after unveiling the original Power Mac G5, Apple released a new line of G5 models, each with dual processors and an 8x SuperDrive. As before, the entry level model uses 64-bit PCI slots and only supports up to 4 GB of RAM vs. PCI-X slots and an 8 GB RAM ceiling in the faster G5s.

The motherboard architecture uses HyperTransport technology. System memory is so fast (400 MHz RAM on a 900 MHz to 1.25 GHz bus) that Apple doesn’t bother with a level 3 cache.

A headphone jack, a USB 2.0 port, and a FireWire 400 port are located on the front of the G5 for easy access.
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The PowerPC 970fx

The second G5 CPU, the PowerPC 970fx, was built on IBM taking its lessons from the first-generation 970, whilst simultaneously pushing towards the 3 GHz goal. The chip maxed out at 2.7 Ghz, still shipping as far along as Early 2005 Power Macs G5s.

The main improvements of the second-generation G5 were the strained silicon, and smaller fabrication size. Strained silicon is a layer of silicon in which the silicon atoms are stretched beyond their normal interatomic distance.

As a result, they fell short of their “GHz” goal, which is partly what prompted Apple to switch to Intel. These chips were also used in the iMac G5 iSight models.
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A new thermal design over the G4

The G5 uses an aluminum enclosure that’s vented in the front and back. The case includes four thermal zones and nine fans to handle cooling, each independently controlled for speed. The 2.5 GHz model incorporates a liquid cooling system to keep the CPU from overheating.

Note that the 1.8 GHz model is one of Apple’s entry-level G5s, which means it uses 33 MHz PCI expansion slots instead of 133 MHz PCI-X andhas 4 memory slots instead of 8.

CPC925 Northbridge Chip

This is an Apple-designed chip made for the Power Mac G5, and used for the first and second generations of PowerPC G5 chips. It is also sometimes referred to as the Apple U3 or U3H (ECC variant) chip, capable of supporting up to two chips.

There are two 550 Mhz unidirectional CPU buses, a 400 MHz DDR memory controller, 8x Pro AGP, and a 400 MHz 16-Bit HyperTransport tunnel.
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What you need to know

• This model is known for being noisy, sometimes being compared to “a jet taking off”. Some users online have reported success installing aftermarket fans for noise reduction.
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• Power Mac G5 Reliability
  • G5/1.8 dual (June 2004), D+ (19%, logicboard, optical drive)
  • G5/2.0 dual (June 2004), C- (17%, logicboard, hard or optical drive)
  • G5/2.5 dual (June 2004), F (26%, logicboard, hard drive)
  • See: Power Mac G5 Overview and Hardware Reliability (Article + MacinTouch 2006 Stats)
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• In each generation, except for the final dual-core one, the fastest model is the least reliable, while the second-fastest is the most reliable. Logicboards are the most expensive component to repair, followed by the power supply. Hard drives, optical drives, video cards, and RAM can be replaced inexpensively using third-party components.
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• Heat Buildup and lack of maintenance can also lead to hardware failure. The underside of the logic board, or at least parts of it, are at risk or are susceptible to heat pockets. A heat pocket is an area where hot air is trapped and cannot easily escape. Although there is a blower-style fan which pulls air up to cool the underside of the logic board which is located next to the hard drives, it cannot compensate for dust buildup or old thermal paste. See suggestions on keeping the Power Mac G5 running cool.
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• Known compatible SSDs:
  
  • Sandisk SSD Plus 2.5″
  • OWC Mercury Electra 3G/6G 2.5″
  • Older Intel SATA SSDs or legacy style SATA SSDs
  • Crucial MX500 M.2 SSD + M.2 to 2.5″ SATA SSD Adapter (by IcyDock)
  • Fanxiang, S&K, Drevo, and other Chinese AHCI style SSDs
  • See: Adding SATA to your PowerPC Mac
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• Top-tier GPU upgrades: ATI Radeon X850XT vs Nvidia GeForce 6800 Ultra DDL
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• Modernizing your Wifi: Add Wifi 4-Draft and Bluetooth 2.1 to your PowerPC Mac
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How it stacks up in Geekbench 2

• Geekbench 2 (Leopard): 2083 (2.5 GHz), 1704 (2.0 GHz), 1553 (1.8 GHz)
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• Geekbench 2 (Tiger): 2105 (2.5 GHz), 1688 (2.0 GHz), 1582 (1.8 GHz)
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Details

• Announced June 9th, 2004
  • Also introduced October 19th, 2004: Single 1.8
• Model Identifier: PowerMac7,3
  • Apple Model Number: A1047 (EMC 1969C)
  • All Power Mac G5s shipped in Silver anodized Aluminum color
• Order Number: M9454LL/A – Dual 1.8 Ghz
  • M9455LL/A – Dual 2.0 Ghz
  • M9457LL/A – Dual 2.5 Ghz
  • M9555LL/A – Single 1.8 Ghz
• All Discontinued April 27th, 2005
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Unsupported macOS

Although it is not supported officially, the Power Mac G5 can run Mac OS X Snow Leopard via a MacRumors build, as well as Sorbet Leopard.
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Mac OS

• Requires Mac OS X 10.3.5 Panther through Mac OS X 10.5.8 Leopard Officially.

Core System

Legend: L1i = L1 Instruction Cache, L1d = L1 Data cache

• ($1999): Dual 1.8 GHz PowerPC 970fx, 2 CPUs, 2 Cores, 64-Bit, 900 MHz System Bus
  90 nm Per-CPU: 64 KB L1i, 32 KB L1d, 512 KB L2, 162x SIMD, AltiVec, 70W+ TDP
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• ($2499): Dual 2.0 GHz PowerPC 970fx, 2 CPUs, 2 Cores, 64-Bit, 1 GHz System Bus
  90 nm Per-CPU: 64 KB L1i, 32 KB L1d, 512 KB L2, 162x SIMD, AltiVec, 110W+ TDP
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• ($2999): Dual 2.5 GHz PowerPC 970fx, 2 CPUs, 2 Cores, 64-Bit, 1.25 GHz System Bus
  90 nm Per-CPU: 64 KB L1i, 32 KB L1d, 512 KB L2, 162x SIMD, AltiVec, 160W+ TDP
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• ($1499): 1.8 GHz PowerPC 970fx, 1 CPU, 1 Core, 64-Bit, 600 MHz System Bus
  90 nm Per-CPU: 64 KB L1i, 32 KB L1d, 512 KB L2, 162x SIMD, AltiVec, 35W+ TDP
  • This is the iMac-based Power Mac G5, with a 3:1 system bus.

Memory

• All 1.8 GHz models: 256 MB – 4 GB 400 MHz PC-3200 DDR SDRAM ~3.2 GB/s
  • These models have a total of 4 RAM slots each.
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• 2.0 and 2.5 GHz: 256 MB – 8 GB 400 MHz PC-3200 DDR SDRAM ~3.2 GB/s
  • These models have a total of 8 RAM slots each.

Video

• For ($1999 and $2499):
  • GeForce FX 5200 Ultra, 64 MB DDR SDRAM @~10.4 GB/s, Rankine, 128-Bit Bus
  • 45 Million Transistors, 150 nm process size, AGP 8x @ 2.14 GB/s
  • 325 MHz GPU clock, 325 MHz Memory clock (650 Mb/s effective), ~20W TDP
  • 4 Pixel Shaders, 4 TMUs, 4 ROPs, DX 9.0a, OpenGL 1.5, Pixel 2.0a Vertex 2.0a
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• ($2999): ATI Radeon 9600 XT, 128 MB DDR SDRAM @~9.6 GB/s, R300, 128-Bit Bus
  • 60 Million Transistors, 130 nm process size, AGP 8x Pro @ 2.14 GB/s
  • 500 MHz GPU clock, 300 MHz Memory clock (600 Mb/s effective), ~22W TDP
  • 4 Pixel Shaders, 4 TMUs, 4 ROPs, DX 9.0, OpenGL 2.0, Pixel 2.0 Vertex 2.0
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• (Optional): ATI Radeon 9800 Pro, 128 MB DDR SDRAM @~21.6 GB/s, R300, 256-Bit Bus
  • 117 Million Transistors, 130 nm process size, AGP Pro 8x @ 2.14 GB/s
  • 378 MHz GPU clock, 338 MHz Memory clock (678 Mb/s effective), ~60W TDP
  • 8 Pixel Shaders, 8 TMUs, 8 ROPs, DX 9.0, OpenGL 2, Pixel 2.0 Vertex 2.0
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• (Optional): ATI Radeon X800XT, 256 MB GDDR3 SDRAM @~32 GB/s, R400, 256-Bit Bus
  • 160 Million Transistors, 130 nm process size, AGP Pro 8x @ 2.14 GB/s
  • 475 MHz GPU clock, 500 MHz Memory clock (1000 Mb/s effective), ~54W TDP
  • 16 Pixel Shaders, 16 TMUs, 16 ROPs, DX 9.0b, OpenGL 2.1, Pixel 2.0b Vertex 2.0b
    • This card was available only from Late 2004/Early 2005 onward.

Drives

• ($1499+): 80 GB 7200 rpm Serial-ATA (SATA), Superdrive 8x (DVD-R/CD-RW) via ATA
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• ($2499+): 160 GB 7200 rpm Serial-ATA (SATA), Superdrive 8x (DVD-R/CD-RW) via ATA

Expansion/Misc.

• 1.8 Ghz Model only: 3x Open-Length, 33 MHz 64-Bit PCI Slots in place of PCI-X slots
  • This applies to the Single CPU and Dual CPU models.
• 2 Ghz and up: 3x Full-Length PCI-X slots: 1x 133 MHz 64-Bit, 2x 100 MHz 64-Bit
• 1x AGP Pro 8x Slot (2.1 GB/s)
• 1x IDE (ATA-6/ATA-100) Port, 2x SATA 1.5 Gb/s (v1.0) Ports
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• 56k v.92 Modem (RJ-11 style connector)
• Front 3.5mm headphone jack
• Optical Audio In/Out
• 1x Rear 3.5mm Audio Out
• 1x Rear 3.5mm Mic/Audio In
  • Compatible with line-level input, not compatible with Apple’s PlainTalk microphone
• 2x FireWire 400
• 1x FireWire 800
• 3x USB-A style USB 2.0 ports
• 1x Gigabit Ethernet (RJ-45 style connector)
• WiFi: antenna and connector for 802.11g AirPort Extreme card
• PRAM battery: 3.6V 1/2AA
• Power Supply: 450W (661-2903) for single CPU models, 600W (661-2904) for duals
  • IEC 60320 C14 Inlet is used for power connection interface on all 3 models.
  • See: Which Power Supply Works in My Power Mac G5?
• Kensington Security Lock

Physical

• size (HxWxD): 20.1″ x 8.1″ x 18.7″ (51.1 x 20.6 x 47.5 cm)
• Weight Dual 1.8 GHz: 44.4 lb. (20.2 kg)
  • Dual 2 Ghz: 39.2 lb. (17.8 kg)
  • Dual 2.5 GHz: 44.4 lb. (20.2 kg)
  • 1.8 GHz PCI Model: 36 Lb. (16.4 kg)

Online Resources

• See: Online resources and links for the Power Mac G5 (Mid 2004)