Developer Documentation
PATHHardware Documentation > Original Power Mac G3 Computers Developer Note


Introduction

The Power Macintosh G3 all-in-one, desktop, and minitower computers are designed around the third-generation PowerPC processor, referred to as the PowerPC G3 or PowerPC 750. The main logic board in all three enclosures has a mini-ATX form factor that supports the PowerPC G3 microprocessor module with a back-side second-level (L2) cache, three PCI card expansion slots, three SDRAM DIMM slots, one SO-DIMM connector for video RAM expansion, and a PERCH slot. The PERCH slot accepts three configurations of Apple Macintosh input/output cards that provide either standard Macintosh sound I/O or enhanced AV features (audio and video input and output)

This note provides a description of the features of the Power Macintosh G3 computers, the logic board architecture and expansion capabilities, and a brief description of the all-in-one, desktop and tower enclosures for the Power Macintosh G3 computer.

This note also provides a list of feature enhancements that were made to the main logic board, the Apple Audio, and the Apple Audio/Video I/O cards. In May `98 changes incorporated into the design of the all-in-one main logic board, consisting primarily of ROM updates and a graphics controller upgrade, were rolled across the entire Power Macintosh G3 product line.

The main logic board of the enhanced configurations is distinguished by the presence of the ATI RAGE PRO graphics controller or by accessing the ROM subversion number programmatically to get the values 0x45F1, or 0x45F2. Models began shipping with the 0x45F2 ROM in August 1998.

Throughout the remainder of this note those features that exist only in the enhanced configurations include a reference to the ROM subversions V4.5 F1 or V4.5 F2. The original Power Macintosh G3 logic board has a ROM subversion of 0x40F2 or V4.0 F2. Prototype sample code that shows how to access the ROM subversion value is provided in Machine Identification .

Power Macintosh G3 Computer Features

Power Macintosh G3 All-in-one Features

Power Macintosh G3 Design Enhancements

External Features

Optional Features

Compatibility Issues

Built-in Video and Graphics Features


© 1998 Apple Computer, Inc. - Revised 8/13/98