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Power Macintosh G3

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The Power Macintosh G3, commonly called "beige G3s" or "platinum G3s" for the color of their cases, is a series of personal computers that was designed, manufactured, and sold by Apple Computer, Inc. from November 1997 to January 1999. It was the first Macintosh to use the PowerPC G3 (PPC750) microprocessor, and replaced a number of earlier Power Macintosh models, in particular the 7300, 8600 and 9600 models. It was succeeded by the Power Macintosh G3 (Blue & White), which kept the name but introduced a radically different design.

The Power Mac G3 introduced a fast and large Level 2 backside cache to Apple's product lineup, running at half processor speed. As a result, these machines were widely considered to be faster than Intel PCs of similar CPU clock speed at launch, an assertion that was backed up by benchmarks performed by Byte Magazine, which prompted Apple to create the "Snail" and "Toasted Bunnies" television commercials.

The Power Macintosh G3 was originally intended to be a midrange series, between the low-end Performa/LC models and the six-PCI slot Power Macintosh 9600.

Apple developed a prototype G3-based six-slot full tower to be designated the Power Macintosh 9700. Despite demand from high-end users for more PCI slots in a G3 powered computer, the prototype was never developed into a shipping product.


[edit] Hardware

The beige Power Macintosh G3 series came in three versions: an "Outrigger" desktop enclosure inherited directly from the Power Macintosh 7300; a minitower similar to (but shorter than) the Power Macintosh 8600 enclosure; and a version with a built in screen, the G3 All-In-One ("AIO"), that was made available only to educational markets. Equipped with a 233, 266, 300, 333, or 366 MHz PowerPC G3 CPU from Motorola, these machines used a 66 MHz system bus and PC66 SDRAM, and standard ATA hard disk drives instead of the SCSI drives used in most previous Apple systems; however, they retained a legacy Fast SCSI chain (up to 5 MB/sec, seven devices internal and external).

The G3 used Apple's new "Gossamer" motherboard, which had originally been developed with an eye towards maximum compatibility with PC components. This was known as the "Yellowknife" project, which had sought to develop the first Apple RISC product — capable of running any OS that would support it, be it Mac OS or Windows. It was an effort by Apple to gain market share, by allowing their hardware to run industry-standard software, but still remaining Mac OS proprietary. The prototype had a ZIF-socket G3 processor, PCI and ISA slots, Mac and PC serial ports, onboard SCSI, PC and Mac floppy drive connectors, ATX power supplies, and PS/2 keyboard and mouse connections, inserted into an ATX case. The project was scrapped by Steve Jobs, after his return to Apple, and his realization of the devastation of Apple's profits due to the clone makers. Remnants of this effort can be seen in production G3's form factor: the logic board's similarity to the PC ATX motherboard standard; solder points for a PC-type floppy drive; and the ability to use both proprietary Apple power supplies and industry-standard ATX power supplies. As a compact and versatile motherboard, the Gossamer board was originally designed to be able to support both the high-end PowerPC 604e and the new PowerPC G3, but when initial tests found that the cheaper G3 outperformed the 604e in many tests, this functionality was removed and Apple's 604e-based systems died a quiet death.

The desktops ranged from 233 to 300 MHz, with the minitowers ranging from 233 to 366 MHz. The 233 and 266 MHz desktop models shipped with 4 GB hard drives, and the 300 MHz with a 6 GB drive, all at 5400 RPM. The 233 MHz minitower shipped with a 4 GB drive, the 266 MHz with a 6 GB drive, and the 300 MHz minitower shipped with two 4 GB drives in a RAID configuration; all models were 5400 RPM. The 300 MHz minitower was replaced by the 333 MHz and finally the 366 MHz towers, each of which shipped with a 9.1 GB 7200 RPM SCSI drive, attached to a SCSI/PCI card — this model also included 100BASE-TX Ethernet (as opposed to the other models' 10BASE-T), though this was in the form of a PCI card, which occupied another PCI slot. Unlike its predecessor, the 300 MHz minitower, the 333 and 366 MHz models had only 6 MiB VRAM, since the 300 MHz model shipped with a 128-bit iXMicro PCI video card with 8 MiB VRAM. The AIO shipped in two basic configurations: a 233 MHz version with a floppy drive and a 4 GB hard drive and a 266 MHz version with a built-in Zip drive, floppy drive, and the "Wings" personality card. Half of the AIO's case was translucent, suggesting what might come with the iMac; it is considered by many to be the precursor to the iMac.

These machines had no audio circuitry on the logic board; instead, a PERCH slot (a dedicated 182-pin microchannel connector; a superset of the PCI spec, but does not accept PCI cards) for a "personality card" was populated with a "Whisper" personality card on regular versions, offering 16-bit, 44.1 kHz audio with simultaneous I/O, or a "Wings" personality card, an AV version which included composite and S-Video capture and output. DVD-ROM drives were now an available option, and Zip drives continued to be available as well.

These machines had onboard and external SCSI (from the custom MESH IC), ADB, 10BASE-T Ethernet, two MiniDin-8 serial ports, and onboard ATI graphics (originally Rage IIc, later updated to Rage Pro and then Rage Pro Turbo) with a slot for VRAM upgrade. Three full-length PCI slots and one internal modem slot, as well as three SDRAM slots (for up to 768 MiB RAM) rounded out the features.

The G3 was the last Macintosh to include built-in serial ports.

Early G3s with Revision A ROMs do not support slave devices on their IDE controllers, limiting them to one device per bus (normally one optical drive and one hard disk). Additionally, they came with onboard ATI Rage II+ video. G3s with Revision B ROMs support slave devices on their IDE controllers, and had the onboard video upgraded to ATI Rage Pro. G3s with Revision C ROMs also support slave devices on their IDE controllers, but the most significant technical differences are the newer Open Firmware version than the previous two models (2.4 vs. 2.0f1) and another onboard video upgrade, this time to ATI Rage Pro Turbo.

The G3 had the largest ROM of any Macintosh to date — 4 MiB. The trend of increasingly large ROMs ended, though, after the introduction of the New World ROM in the iMac, and then the B&W Power Macintosh G3.

[edit] Upgradeability

  • The Gossamer logic board has three full-length (12") PCI slots, making it capable of taking any PCI cards that have Macintosh drivers available for them (for example, some RealTek-based network adapters, a lot of USB, ATA/IDE [or SATA] and FireWire cards). The most common PCI card upgrades normally added to Beige G3 Power Macs are FireWire cards, USB cards and FireWire/USB combo cards (especially after the release of the first generation iMac, which caused many vendors to start releasing FireWire and USB peripherals for the Macintosh), 100BASE-TX or 1000BASE-T (gigabit ethernet) network adapter (for those who need faster than the onboard 10BASE-T), video cards (ATI Radeon 7000 and 9200 cards are a popular choice), ATA/EIDE, Serial ATA and Ultra SCSI cards. Television tuner and radio cards are also often chosen to supplement the AV features on a Wings personality card, or to provide A/V input for models with the Whisper personality card.
  • Some users have upgraded the Whisper personality card in their Beige G3s with a "Wings" Personality card (which is plugged into the same PERCH slot), and some have upgraded the ROM on their Beige G3s to a newer version (Revision A boards to Revision B or Revision C boards).
  • For storage, the G3 is capable of taking any ATAPI/IDE hard disks, provided that the drive's size is within the 28-bit LBA limit. This means a G3 is capable of supporting ATA hard disks of up to 137 GB (228 blocks of 512 bytes each). This limitation can be overcome by using a IDE or SATA PCI-compatible card (e.g. Acard or Sonnet) to allow the G3 to use a maximum of 2 drives over the 137 GB limit.
  • The ATAPI/IDE CD-ROM drive can also be replaced with a CD-RW, DVD-ROM or DVD-RW drive, although care must be taken while purchasing the upgrade as the Mac is incompatible with some drives and may refuse to boot at all if an incompatible drive is installed. Also, many third-party optical drives cannot be used as boot devices with the G3, though they work correctly for normal use. It is also capable of taking SCSI storage devices, and with the presence of the right PCI cards, SATA, USB and FireWire storage devices.
  • The presence of an onboard SCSI controller (the SCSI controller is codenamed MESH — Macintosh Enhanced SCSI Hardware) and connectors permits the use of Mac-enabled SCSI scanners and storage devices, though this runs at only 5 MB/s.
  • The G3 can support up to 768 MiB of SDRAM in any configuration (although incompatibility has been reported with some DIMM modules in certain configurations). It should be able to take 168-pin SDRAM of any speed, though it will run at PC66 speeds. The onboard video RAM can be upgraded from 2 MiB to 6 MiB with a 4 MiB SGRAM module (which runs at 83 MHz on Rev. A machines, and 100 MHz on Rev. B and C machines).
  • The G3 processor module (a PowerPC 750 plus L2 cache) can be easily changed to the faster model, i.e. 333MHz and even 366MHz (rare). Consult a Clocking the Power Mac G3 article for more info.
  • The CPU can be upgraded with a G4 processor of up to 1.0 GHz using upgrade kits from third party vendors, although the user would not see much practical difference in performance on chips faster than 733 MHz due to the system bus limitations, which runs at 66.83 MHz unless overclocked. However, G4 chips running over 533 MHz do not allow the system bus to run faster than 66 MHz, so you cannot overclock the bus if you wish to use one of these G4s. (G3s do allow it.)
  • The G3 officially supports up to Mac OS X 10.2.8, although some devices will not work under Mac OS X, such as the floppy drive, the video features of the "Wings" personality card, and the 3D graphics acceleration functions of the onboard ATI Rage series video. Support for newer versions is possible with the use of third party solutions such as XPostFacto, albeit with a few tradeoffs and catches -- the biggest being the lack of support by Apple and the fact that a supported PCI video card must be present as support for the onboard ATI Rage series video was dropped completely as of Mac OS X 10.3.

[edit] Sources

[edit] External links

This article was started using a Wikipedia Macintosh G3 article
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