FireWire 800 Power Mac G4

The January 2003 Power Mac G4 was the first to require OS X. It was also the first with FireWire 800 ports. A good rule of thumb: If it has FireWire 800, it isn’t meant to boot OS 9, although we have heard of a workaround. The FireWire 800 model was also the first Power Mac with a Bluetooth socket and support for 802.11g AirPort Extreme.

FireWire 800 Power Mac G4Apple hit the 1 GHz mark in January 2002, 1.25 GHz in August 2002, and 1.42 GHz in January 2003. At the bottom of the new series, Apple dispensed with dual processors to keep the price down – the 1.0 GHz single CPU model retailed for just $1,499.

Still, Motorola remained “behind the curve” with G4 processor speeds, which, extrapolated from Moore’s Law, should increase roughly 25% every six months. Instead, we have a decidedly overhyped 14% jump in CPU clock speed. On the other hand, the price is 18% lower, further improving the value of the Power Mac G4.

As with the previous revision, the two faster models have a 167 MHz system bus. All models have two media drives bays (so you can have a SuperDrive and a fast CD burner or a second SuperDrive), four RAM sockets, and three independent drive buses that each support two devices. An Ultra ATA/33 (ATA-4) bus is used for the optical drive(s), Ultra ATA/100 (ATA-6) connects to the stock hard drive, and there’s also a normally unused Ultra ATA/66 (ATA-5) bus. Only the ATA/100 connector supports drives over 128 GB capacity. There are four 3.5″ hard drive bays inside the G4.

The fastest pair of new G4s have faster video cards, the ATI Radeon 9000. The dual 1.42 GHz model includes 2 MB of level 3 cache per processor, twice as much as the slower models.

Watch out for Apple’s claim of “four USB ports” – there are two on the computer and two on the keyboard, so once you’ve plugged in the keyboard, you’re down to three available. Make that two after you plug in the mouse. Your best bet here is to add a USB 2.0 PCI card, which also overcomes the speed limitations of this Mac’s built-in USB 1.1 ports. has documented a process for downgrading the firmware of this model so it can natively boot Mac OS 9. We’re hoping to find someone who has done the procedure who can distill this long thread into a more easily followed step-by-step process.

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  • Our Mac OS 9 Group is for those using Mac OS 9, either natively or in Classic Mode.
  • Our Jaguar Group is for those using Mac OS X 10.2.
  • Our Panther Group is for those using Mac OS X 10.3.
  • Our Tiger Group is for those using Mac OS X 10.4.
  • Our Leopard Group is for those using Mac OS X 10.5 and 10.6.


  • Introduced 2003.01.28 with 1.0 GHz single CPU, 256 MB RAM, 60 GB hard drive, Combo drive, and GeForce 4x graphics at $1,499; reduced to $1,149 on 2003.06.23. 1.25 GHz dual 256 MB/80 GB/Combo/Radeon 9000 introduced at $1,999; reduced to $1,699 on 2003.06.23. 1.42 GHz dual 512 MB/120 GB/SuperDrive/Radeon 9000 introduced at $2,699; reduced to $2,399 on 2003.06.23. Replaced by Power Mac G5 in mid 2003.
  • requires Mac OS X 10.2 Jaguar through 10.5 Leopard
  • CPU: 1.0/1.25/1.42 GHz PowerPC 7455
  • Bus: 133 MHz on 1.0 GHz model, 167 MHz on faster ones
  • Performance:
    • Geekbench 2 (Leopard): unknown (1.42 GHz dual), 1047 (1.25 GHz dual), 576 (1.0 GHz single)
    • Geekbench 2 (Tiger): 1165 (1.42 GHz dual), 1048 (1.25 GHz dual), 570 (1.0 GHz single)
  • RAM: 256/512 MB standard, expandable to 2 GB using PC2100 memory in 4 DIMM slots in 1.0 GHz model, PC2700 memory in faster models
  • Video: Nvidia GeForce 4 on 1.0 GHz model, ATI Radeon 9000 Pro on faster models; DVI and ADC ports, includes DVI-to-VGA adapter
  • VRAM: 64 MB
  • L2 cache: 256 KB on-chip L2 cache
  • L3 cache: 1 MB on 1 GHz model, 1 MB per CPU on 1.25 GHz model, 2 MB per CPU on 1.42 GHz model
  • Hard drive: 60/80/120 GB 7200 rpm ATA/100
  • Combo (CD-RW/DVD) on 1.0 and 1.25 GHz models; SuperDrive standard on 1.42 GHz model, optional on others
  • internal Zip 250 drive (optional)
  • 4 64-bit PCI slots
  • Modem: internal 56k v.92
  • Microphone: standard 3.5mm minijack, compatible with line-level input, not compatible with Apple’s PlainTalk microphone
  • FireWire 400: 2 ports
  • FireWire 800: 1 port
  • USB: 2 USB 1.1 ports
  • Ethernet: 10/100/gigabit
  • WiFi: antenna and connector for 802.11g AirPort Extreme card
  • size (HxWxD): 17.0″ x 8.9″ x 18.4″
  • Weight: 42.0 lb.
  • Gestalt ID: n/a
  • PRAM battery: 3.6V half-AA
  • upgrade path: none yet, although CPU upgrades are likely
  • Part no.: M8689 (1 GHz), M8840 (1.25 GHz), M8841 (1.42 GHz)

Accelerators & Upgrades

Online Resources


  • Leopard (Mac OS X 10.5) boot times for Power Mac with the GeForce 6200 fall into the 4-5 minute range, and was initially suggested that you install Leopard with the Mac’s original video card to avoid slowing down the process. “gotoh” has posted the fix in The Mac Elite Forum. The delay is due to Leopard not supporting temperature sensors in G4 Macs. Simply remove AppleHWSensor.kext from /System/Library/Extensions, and the delay goes away.
  • Note that some vendors are substituting PC2700 RAM for PC2100 modules. Although PC2100 Macs can work with PC2700 RAM, you can’t use both types of RAM in the same machine. All installed RAM must be the same type, whether PC2100 or PC2700.

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