Mirrored Drive Doors Power Macintosh G4

Apple hit the 1 GHz mark with the Quicksilver 2002 in January 2002 and 1.25 GHz with the Mirrored Drive Door (MDD) in August 2002. Even the entry level 867 MHz Power Mac G4 now has dual processors. This was the last Power Mac to natively boot Mac OS 9.

Mirrored Drive Doors Power Mac G4

MDD Power Mac G4

The two faster versions introduced a 167 MHz system bus. All models now have two full size media drive bays (so you can have a SuperDrive plus a fast CD burner or two SuperDrives), 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 an 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.

Although the MDD Power Macs support up to 2 GB of RAM, Mac OS 9 is only able to recognize up to 1.5 GB of RAM.

Beware Apple’s claim of “four USB ports” – there are two on the computer and two on the keyboard, just like previous G4s, so with the keyboard plugged in, you only have three available. That drops to two available when a USB mouse is plugged in.

The fastest pair of MDD G4s have faster video cards, the ATI Radeon 9000. The dual 1.25 GHz model includes 2 MB of level 3 cache per processor, twice as much as the slower models.

You should have the most recent firmware installed in your Power Mac G4. The newest version for Mirrored Drive Doors models is Power Mac G4 Firmware Update 4.4.8, which is only for Mirrored Drive Doors Power Mac. To install this firmware update, you must boot into Mac OS 9.2.2 from a writable partition (not a CD).

Two Versions

The 2002 and 2003 Mirrored Drive Door models look the same, and the dual 1.25 GHz version has exactly the same specs, but there are differences, as discovered by Jay at The House of Moth:

  • The 2003 logic board is a bit smaller, has improved airflow, and only supports a 1.67 GHz system bus.
  • The 2002 case uses more metal and has better cooling than the 2003 case.

In the end, The House of Moth put the guts of a 2003 MDD into the superior 2002 MDD case, creating a FrankenMac with the best features of each revision.

Keeping It Cool

Two CPUs can run fairly hot. Use good thermal paste (Arctic Silver is one, and you should probably reapply every few years) or a really good thermal pad. Consider replacing some of the fans with ones that move more air (and, in some cases, will also reduce fan noise).

But here’s the biggie: The Power Mac G4 (FW800) uses a copper heatsink, and The House of Moth has tested it against the aluminum heatsink in the original MDD model. The copper heatsink runs cooler by roughly 5°F (2.7°C). If you need/want a Mac that still natively boots Mac OS 9, this is one more thing to help it keep its cool.

A Better Video Card

For everyday use, the stock video cards are just fine, but if you’re into gaming with this PPC Mac, you will want a better video card than the ATI Radeon 9000 Pro, which in some games will drop below 10 FPS. Again, The House of Moth provides an answer. By modifying an ATI Radeon 9650 from a Power Mac G5, performance in the OpenGL benchmark quadrupled compared to the 9000 Pro! This card also has 128 MB or, if you are lucky, 256 MB of video memory, which also helps with gaming performance.

“Games fly, even with all settings maxed out at full resolution. The card does run hot so I keep game settings medium-high until I can whack a fan on it or find another cooling solution.”

But you know gamers: Always looking for improved performance, and when Greg Hrutkay recommended the ATI Radeon X850 Pro with 256 MB of video memory to The House of Moth, they found one on eBay and installed it. As of Sept. 2018, we don’t have any more information on this upgrade, because the video card purchased on eBay is broken.


  • G4/867 MHz dual 256/60/Combo/GeForce 4 MX introduced 2002.08.13 at $1,699
    G4/1.0 GHz dual 256/80/Combo/Radeon 9000 Pro introduced 2002.08.13
    G4/1.25 GHz dual 512/120/SuperDrive/Radeon 9000 Pro introduced 2002.08.13; reduced to $1,299 on 2003.06.23 as a 256/80/Combo model
  • Requires Mac OS 9.2 or OS X 10.2 Jaguar through 10.5 Leopard
  • CPU: 867 MHz/1.0/1.25 GHz PowerPC 7455
  • Bus: 133 MHz on 867 MHz model; 167 MHz on faster models
  • Performance:
    • Geekbench 2 (Tiger): 1047 (1.25 GHz), 874 (1.0 GHz), 724 (867 MHz)
    • Geekbench 2 (Tiger): 1048 (1.25 GHz), 862 (1.0 GHz), 722 (867 MHz)
  • RAM: 256/512 MB standard, expandable to 2 GB (although Mac OS 9 will only recognize 1.5 GB) using PC2100 memory in 4 DIMM slots in 867 MHz model, PC2700 memory in faster models
  • Video: Nvidia GeForce 4 MX on 867 MHz model, ATI Radeon 9000 Pro on faster models; AGP 4x; DVI and ADC ports, includes DVI-to-VGA adapter
  • VRAM: 64 MB
  • L2 cache: 256 KB on-chip L2 cache
  • L3 cache: 1 MB per CPU on 867 MHz and 1 GHz models, 2 MB per CPU on 1.25 GHz model
  • Hard drive: 60/80/120 GB 7200 rpm ATA/100
  • Combo (CD-RW/DVD) on 867 and 1.0 GHz models; SuperDrive (4x DVD, 2x DVD-R) standard on 1.25 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
  • USB: 2 USB 1.1 ports
  • Ethernet: 10/100/gigabit
  • antenna and connector for AirPort 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
  • Order no.: M8787 (867 MHz), M8689 (1 GHz), M8573 (1.25 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 it 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 shouldn’t use both types of RAM in the same machine. All installed RAM should be the same type, either PC2100 or PC2700.

Short link: http://goo.gl/9h6ArQ

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