Beige Power Mac G3 (1998)

Code named Gossamer, this faster version of the Beige G3 builds on Apple’s success with the 233 and 266 MHz Late 1997 models. In addition to a 300 MHz PowerPC 750 (a.k.a. G3) CPU, the 300 MHz model has the option of a 1 MB backside cache – twice as big as in the earlier models. Apple also offered a 4 GB ultra wide SCSI drive as an option, which offers better performance than the EIDE drive in the 233 and 266 MHz models.

Beige Power Mac G3If you have an IDE hard drive larger than 8 GB, you should partition it so that the first partition is under 8 GB in size (for simplicity, we suggest 7 GB). Failure to do this could eventually result in an unbootable computer, as all system files must be within the first 8 GB of drive space. These Macs may work successfully with larger drives for some time, but once any system files goes outside of the first 8 GB of space, you’ll have nothing but problems. This applies to both Mac OS X and the Classic Mac OS.

Mac OS X

Beige Power Mac G3 towerIf you have an IDE hard drive over 8 GB in size, you must partition it or you will not be able to install Mac OS X. If you are creating the partition within OS X, it must be smaller than 7.4 GB as reported by Disk Utility (because sometimes a GB is billion bytes and sometimes it’s 1,073,741,824 bytes); we suggest simply setting it at 7 GB to avoid having to redo the whole installation if the partition ends up bigger than specified (it happens). Mac OS X must be completely within the first 8 GB of space on your hard drive or you will not be able to run OS X.

You can only boot OS X from a “master” drive in the Beige G3. This applies to hard drives and CD-ROM drives. If the CD-ROM is set to slave, you will not be able to install OS X. If the hard drive is set to slave, you will not be able to boot from it.

Non-Apple upgrades and peripherals (such as unsupported USB devices, replacement drives, and third-party memory) may cause problems when installing or booting into Mac OS X.

Be sure to read and follow Apple’s “Read Before You Install” instructions to increase the likelihood of getting OS X installed and running on the first try.

The Beige G3 is not officially supported under OS X 10.3 or later, but it does work with 10.2.8 and earlier. Panther can be installed using XPostFacto 3, although built-in video is not currently supported.


Data on the RAM Disk is lost during a restart, unlike earlier Macs. Apple also notes that the 100 MHz Pentium PC Compatibility card is incompatible, although this seems to be due to an audio cable problem. There are also reports that the G3 will not stay asleep.

Other compatibility issues:

  • GeoPort Modem not supported
  • QTC and AMC not supported
  • Must disconnect LocalTalk if using ethernet
  • Needs updated drivers for StyleWriter 4100 & 4500
  • Needs new ethernet driver for use on 10/100 autosensing hubs
  • LocalTalk printing slow on busy networks
  • Apple TokenRing card not supported

Some of these issues were addressed by later versions of the Mac OS.

When buying a G4 upgrade for the Beige G3, make sure it is compatible with this model’s 66 MHz bus. Pulled G4s from Apple’s Yikes! G4 and some OEM G4s are specifically designed for a 100 MHz bus and will not work properly in the Beige G3.

Because of the case design, be sure to specify low profile (1.15″ maximum height) DIMMs when purchasing memory for the desktop version.

The Beige G3 supports 256 MB DIMMs, but they must be built using 128 Mb chips. DIMMs built with 256 Mb chips will work, but the memory controller will only see the first 128 Mb of each chip. Compatible 256 MB DIMMs will have 16 memory chips, eight on each side.


  • introduced 1998.03.17 at 300 MHz; 333 and 366 MHz versions introduced 1998.08.12; discontinued 1999.01.01
  • Support Mac OS Versions
  • CPU: 300 MHz PPC 750
  • Bus: 66 MHz
  • CPU performance
    • 300 MHz: 1041, MacBench 4; 1000, MacBench 5, 38,889 (300 MHz) Whetstones
    • 333 MHz: 1111, MacBench 5
  • L2 cache: 1 MB 2:1 backside cache
  • RAM: at least 32 MB (expandable to 768MB, desktop version requires low profile DIMMs), uses 3.3V unbuffered 100 MHz 168-pin SDRAM, 3 sockets accept 8, 16, 32, 64, 128, or 256MB DIMMS (some tall DIMMs may not fit desktop case)
  • VRAM: 2 MB SGRAM, expandable to 4 or 6 MB, uses 3.3V 83 MHz 144-pin SO-DIMM
  • Video: supports resolutions to 1280 x 1024, uses ATI Rage Pro chip
  • Hard drive: various 4 GB and larger IDE and SCSI drives, varies by configuration. Maximum IDE drive size is 128 GB without third-party support. See How Big a Hard Drive Can I Put in My iMac, eMac, Power Mac, PowerBook, or iBook? for three options.
  • there is an internal SCSI connector on the Revision 2 motherboard
  • CD-ROM: 24x maximum throughput, DVD-ROM optional (requires a 3rd-party solution for MPEG-2 video playback)
  • internal Zip drive available, standard on some models
  • 3 PCI slots
  • 1 Personality Card slot (matches Comm Slot II; supports DVD, AV input/output, 128-bit graphics, and FireWire cards)
  • Microphone: standard 3.5mm minijack, compatible with line-level input including Apple’s PlainTalk microphone
  • ADB: 1 port for keyboard and mouse
  • serial: 2 DIN-8 GeoPorts on back of computer
  • SCSI: DB-25 connector on back of computer
  • Ethernet: AAUI and 10Base-T connectors on back of computer
  • size, desktop (HxWxD): 6.3″ x 14.4″ x 16.9″
  • size, mini tower (HxWxD): 15.2″ x 9.6″ x 17.8″
  • weight, desktop: 22.0 lbs.
  • weight, mini tower: 33.1 lbs.
  • Gestalt ID: 510
  • PRAM battery: 3.6V half-AA
  • upgrade path: G3 and G4 ZIF CPU upgrades (note that maximum CPU speed you can set using the J16 jumper block is 466 MHz – 7 times bus speed – unless the upgrade sets its own multiplier)

Accelerators & Upgrades

Online Resources


  • Power Macs earlier than the Quicksilver models do not have built-in support for IDE hard drives with capacities over 128 GB. Without a third-party solution, larger drives can only be formatted to 128 GB in these models. There are three options:
  • Apple has discovered the cause of the dim video problem with the audio/video personality card in the Power Mac G3s. Contact Apple or your Apple dealer for a new card that fixes the problem.
  • If you have a Revision 2 motherboard (one way to tell: the System CD is blue, not white), your G3 supports up to 4 IDE/ATA drives. However, it cannot boot from an internal ATAPI Zip drive (which is what Apple installs with the Rev. 2 board) unless the disk has Iomega driver 6.0 or later with Enabler 777 in the Mac OS 8.1 System Folder. Earlier Iomega drives do not support ATAPI Zip drives. (Apple TIL)
  • Macs with IDE hard drive do not provide SCSI termination power, depending on external SCSI devices to provide it. For more details, see SCSI Termination Power.

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