Apple Mac G4 Powermac 400mHz system (PCI)

PowerMac G4 400mHz PCIThe G4 400mHz powermac is a G4 based Apple Macintosh system. Based on the yikes motherboard (as with G3 blue and white towers) it contains PCI slots and a PCI graphics card, all in a stylish computer case with fold-down side door. It lacked any floppy drive or mouse. This, luckily, is not an issue as floppy disks are a thing of the past!

Note: The G4/PCI (yikes) cannot use the latest high-density RAM modules  which are compatible only with the later Mac models (G4/AGP systems). If a 256MB dimm is used and it has only 8 ram chips on it, it will only be recognized as a 128MB dimm.  As a result, 256MB DIMMS must have 16 chips (8 chips to each side) on it to function as 256MB. Also note that these systems, unlike beige powermacs, will work directly with any SVGA (dsub15) driven PC monitor.

These Macs  have built in USB, Ethernet, firewire, modem and the usual plethora of ports. These systems are extremely stable when running mac OS, and can take Mac OS X tiger (10.4) system without any discernable drop in performance.


The Apple Power Macintosh G4/400 (AGP Graphics), based on the Sawtooth architecture, features a 400 MHz PowerPC 7400 (G4) processor with the AltiVec “Velocity Engine” vector processing unit and 1 MB of backside cache. It shipped configured with 64 MB or 128 MB of RAM, a 10 GB or 20 GB Ultra ATA/66 hard drive, a 5X DVD-ROM drive, and either a 2X AGP ATI Rage 128 or Rage 128 Pro graphics card with 16 MB of SDRAM. AirPort (802.11b) was available by custom configuration.

Graphics & Video:

The G4 400mHz PCI shipped with an  ATI Rage 128 graphics card with 16 MB of SDRAM occupying a 66 MHz PCI slot. Apple advertised that this system can support “up to 1600 by 1200 pixel resolution at 32 bits per pixel (millions of colors) and up to 85-Hz refresh rate.”


In the default configuration, this model has three open 33 MHz PCI slots and a 66 MHz PCI slot occupied by the graphics card. It has five 3.5″ drive bays (four are internal and intended for hard drives, and one is external and intended for a Zip 100 drive). By default, with a single drive installed, three internal 3.5″ bays are free as is the external 3.5″ bay. The system also has an external 5.25″ drive bay occupied by the optical drive. Howver, it only contained 2 IDE chains, supporting a total of 4 ide Drives.

Hard Drive Support:

The G4/400 PCI officially support two Ultra ATA/33 hard drives on the original bus (more drives can be supported with a third-party controller PCI card). As with all graphite G4 systems,  drives larger than 128 GB are not natively supported. Ultra ATA/100 hard drives are backwards compatible with the Ultra ATA/33 standard. The G4/400 could also be configured with up to three Ultra2 SCSI drives at the time of purchase as a build-to-order option.

Introduction Date: August 31, 1999 Discontinued Date: October 13, 1999*
Details: The “Introduction Date” refers to the date a model was introduced via press release. The “Discontinued Date” generally refers to the date a model either was replaced by a subsequent system or production otherwise ended.*The lifespan of this model was cut short by Motorola’s inability to provide sufficient numbers of PowerPC 7400 (G4) processors, causing Apple to quickly, and infamously, “reconfigure” or “speed dump” this model
Processor Speed: 400 MHz Processor Type: PowerPC 7400 (G4)
Details: The PowerPC G4 includes the AltiVec “Velocity Engine” vector processor.
Processors: 1 Geekbench: 247
Processor Upgrade: ZIF Socket FPU: Integrated
Details: The Power Macintosh G4 (PCI Graphics) models have the processor mounted on a ZIF socket.
System Bus Speed: 100 MHz Cache Bus Speed: 200 MHz
Details: This system has a 200 MHz backside bus and 1 MB of level 2 cache.
ROM/Firmware Type: Open Firmware ROM/Firmware Size: 1 MB
Details: Boot ROM and around 1 MB, other instructions are loaded into RAM (NewWorld).
L1 Cache: 64k L2/L3 Cache: 1 MB (backside)
Details: The 1 MB of backside cache has a 200 MHz bus.
RAM Type: PC100 SDRAM Min. RAM Speed: 100 MHz
Details: Officially supports 100 MHz PC100 SDRAM (3.3v, unbuffered, 64-bit-wide, 168-pin), but PC133 SDRAM is backwards compatible and may be used as well.
Standard RAM: 64 MB Maximum RAM: 1 GB
Details: Installed as a single 64 MB module. There is no performance advantage to installing memory modules in pairs.
Motherboard RAM: None RAM Slots: 4
Details: There is no performance advantage to installing memory modules in pairs.
Video Card: Rage 128 VRAM Type: SDRAM
Standard VRAM: 16 MB Maximum VRAM: 16 MB
Details: N/A
Display Support: Single Display Resolution Support: 1600×1200
2nd Display Support: None 2nd Max. Resolution: N/A
Details: N/A
Standard Hard Drive: 10 GB (5400 RPM) Int. HD Interface: Ultra ATA/33 (ATA-4)
Standard Optical: 32X CD-ROM Standard Disk: None*
Details: The 32X CD-ROM drive uses a EIDE (ATA-3) bus. Optional 5X DVD-ROM or DVD-RAM drives were available build-to-order.*By default, this model shipped without a disk drive, but it could be configured with an internal Zip 100 drive as a build-to-order option.
Standard Modem: 56k Standard Ethernet: 10/100Base-T
Details: Internal modem and 10/100Base-T Ethernet standard.
Standard AirPort: None Standard Bluetooth: None
Details: N/A
USB Ports: 2 (1.1) Firewire Ports: 2 (400)
Details: USB 1.1 ports share a single channel.
Expansion Slots: 3 PCI* Expansion Bays: 5 3.5″
Incl. Keyboard: Apple USB Keyboard Incl. Input: Apple USB Mouse
Details: N/A
Case Type: Tower Form Factor: Power Mac G4 (Graphite)
Apple Order No: M7631LL/A Apple Subfamily: Power Mac G4 – PCI
Details: The Apple order number should be unique to this system.
Apple Model No: M5183 (EMC N/A) Model ID: PowerMac1,2
Details: Please note that these identifiers refer to more than one model.
Battery Type: 3.6V Lithium Battery Life: N/A
Details: N/A
Pre-Installed MacOS: 8.6 Maximum MacOS: X 10.4.11
Details: This system cannot run versions of MacOS X more recent than 10.4.11.
MacOS 9 Support: Boot/Classic Mode Windows Support: Emulation Only
Details: This Power Macintosh G4 model is capable of booting Mac OS 9 and using Mac OS 9 applications within the Mac OS X “Classic” environment.
Dimensions: 17.0 x 8.9 x 18.4 Avg. Weight: 30.0 lbs. (13.6 kg)