Power Mac G3 All-In-One

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The Power Macintosh G3 All-In-One (AIO), originally available only via educational sales channels, has three SDRAM expansion slots. As the Grackle IC memory controller and PCI bridge on the "beige" logic board supports only linear memory organization, no benefit accrues from installing SDRAM DIMMs in matched pairs, and DIMMs (installed in any slot and any order) are addressed as a contiguous memory array.

Although Apple technical documents state that the densest DIMM supported by the "beige" main logic board is a dual-banked 128MB DIMM using a maximum of sixteen 64Mbit SDRAM devices, testing has demonstrated that max configurations of 768MB are feasible in these three-slot machines using three 256MB SDRAM DIMMs employing thirty-two CMOS 16Mx4 bit Synchronous-DRAM devices in a 1.15-inch high form factor. These DIMMs are appropriate for use in the AIO, and are designed to support bus speeds of 66MHz, 83MHz, and 100MHz.

With the exception of the 256MB SDRAM DIMM, all other pieces are fully compliant with Apple specifications--with the additional and desirable exception of being only 1.15-inches tall: any SDRAM DIMM sold by MacGurus will handily fit in the AIO without difficulty.

Important: Power Mac G3 Desktop computers use SDRAM DIMMs. DIMMs from older Macintosh computers are not compatible and should not be used even if they fit into the Power Mac G3 AIO SDRAM DIMM slots.

The Power Mac G3 AIO logic board ships with 2MB Synchronous Graphic RAM (SGRAM) video memory soldered to the logic board. The logic board includes a video memory expansion slot that accepts a Small Outline DIMM (SO-DIMM) to increase video memory to a maximum of 6MB. Apple supports a 4MB SGRAM SO-DIMM that is 32-bit wide, 144-pin, fast-paged, 83 MHz/12 ns or faster.

Important: Use only SGRAM SO-DIMMs to upgrade video performance in the AIO. Never use older 256K or 512K video memory DIMMs from older computers.

Power Macintosh AIO G3 computers require an I/O card that handles audio and/or video from the main logic board. These cards are placed in the PERCH connector on the main logic board. Reseating this board solves most common problems reported with this system.

Note: The Power Macintosh AIO G3 computers will boot without an I/O card installed. However, they will not operate correctly without it.

Logic Board Revisions

The three logic board revisions mostly affect the "beige" G3 line (Gossamer and Artemis, including the AIO). The first revision, Rev 1, is characterized by a Rage IIc graphics chip, and no support for IDE slave devices. Also, the first revision logic board includes a slower 233MHz or 266MHz G3 processor chip. The second revision, Rev 2, incorporates a Rage Pro graphics chip, and support for IDE slaves. This revision includes a faster G3 processor chip running at either 300 or 333 MHz. The third revision to the G3 logic board was the totally revamped Yosemite Blue and White G3 Logic Board. This revision incorporates Rage 128 graphics on a PCI video card, IDE master/slave support and a G3 processor running at 350, 400, or 450 MHz.

Using Apple System Profiler (ASP), located under the Apple menu, you can determine which logic board revision you have in your beige G3. Open Apple System Profiler, click the System Profile tab, and then look at the Production Information section. Compare it to the table below to determine which revision of the logic board is in your Power Macintosh G3 computer.

ROM Versions Logic Board Revision
$77D.40F2 Revision 1
$77D.45F1 Revision 2
$77D.45F2 Revision 3

Note: All Power Macintosh G3 All-in-one computers and (platinum) Power Macintosh G3 300Mhz and 333Mhz Desktop/Minitower computers have revision 2 logic boards.

Master/Slave Configuration Support

Some Power Macintosh G3 computers and all Power Mac G4 computers can support two ATA/IDE devices on the same ATA/IDE channel. This is commonly referred to as a "master/slave" configuration. The Power Macintosh G3 Minitower, Power Macintosh G3 Desktop, and Power Macintosh G3 All-In-One computers were the first Macintosh computers to use master/slave configurations. Macintosh computers introduced prior to these, including those with internal IDE buses, do not support this feature.

Support for a master/slave configuration permits the addition of ATA/IDE hard drives or removable media drives.

You can install two ATA/IDE devices on the same ATA/IDE channel in a master/slave configuration on these computers:

The Power Macintosh G3 (Blue and White) computers that support dual IDE drives have a U bracket installed in the rear drive bay. This allows two hard drives to be installed in that bay.

The original Power Macintosh G3 Minitower and Desktop computers may or may not support this feature. Only Power Macintosh G3 Minitower and Desktop computers with Rev 2 logic boards or later support master/slave configurations. Apple System Profiler will confirm which logic board revision is installed in your computer. It is also possible to use the Apple System Profiler to confirm which ATI Rage graphics accelerator chip is on the logic board. If ASP reports the presence of an ATI RAGE PRO on the logic board, the computer has a Rev 2 logic board.

Configuring and Connecting

Important: The following information is valid only for Power Macintosh G3 computers that support master/slave configurations.

Each IDE channel can handle one or two devices, each with integrated controllers. To maintain order on the channel, it is necessary to differentiate between devices. This is done by designating each device as either master or slave, using small plastic connectors (known as jumpers) over pairs of pins which program the drive. Manufacturers use different pin/jumper configurations to program drives, so you will need to consult the documentation pertaining to your specific drive to confirm its correct settings.

ATAPI drives, or ATA/IDE devices that support removable media like CD-ROM drives, are jumpered in the same way.

If you are using two drives on one channel, make sure they are jumpered. Setting both drives as master, or slave, may cause unpredictable behavior.

It makes no difference which connector on the ATA/IDE cable is used in a standard ATA/IDE setup because the jumpers control master and slave status, not the cable. As long as one device is jumpered as master and the other as slave, any two ATA/IDE or ATAPI devices should work together on a single channel.

Logic Board RAM None
Supported DIMMs 4MB, 8MB, 16MB, 32MB, 64MB, 128MB, and 256MB.
Number DIMM Slots Three (3)
Supported VRAM 2MB expandable to 4MB or 6MB using 32-bit wide, 144-pin, 3.3 V, SGRAM SO-DIMM
Number VRAM Slots One (1)
L2 Cache Supported? Supports 512K-1MB backside L2 cache on ZIF processor.
DIMM Type 168-pin, 3.3v PC-100 64-bit, 10ns/125MHz SDRAM.

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