The Power Macintosh G3 Minitower (Artemis) has three SDRAM expansion slots. As the Grackle IC memory controller and PCI bridge on the Gossamer and Artemis logic boards 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 Gossamer and Artemis main logic boards 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 either Desktop (DT) or MiniTower (MT) versions of the beige Macintosh G3, and are designed to support bus speeds of 66MHz, 83MHz, or 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 on our beige G3 SDRAM page will handily fit in either the Apple G3 DT or MT without difficulty.
Important: Power Macintosh G3 Minitower and Desktop computers use SDRAM DIMMs. DIMMs from older Macintosh computers are not compatible and should not be used, even if they physically fit into the Power Macintosh G3 Minitower or Desktop SDRAM DIMM slots.
The Power Macintosh G3 Minitower logic board features 2MB soldered Synchronous Graphic RAM (SGRAM) video memory. Video SGRAM may be upgraded using a video memory expansion slot that accepts Small-Outline DIMMs (SO-DIMM) to increase video memory to a maximum of 6MB. Apple supports a 4 MB SGRAM SO-DIMM that is 32-bit wide, 144-pin, fast-paged, 83 MHz/12ns or faster.
Important: Use only SGRAM SO-DIMMs. Do not attempt to use 256K or 512K video memory DIMMs from older computers.
Logic Board Jumper Settings
Power Macintosh G3 Desktop, G3 Minitower, and Macintosh Server G3 computers use identical (or very similar) logic boards, but jumper settings differ between them.
The jumper block at location J16 configures the board for different processor modules. Use the appropriate jumper block, identified by color, for each processor module.
Processor Speed Jumper Color 233 Red 266 White 300 Black
Jumper location J28 controls which power supply the logic board can accommodate. If you are working with a raw logic board (a service part), you must place the jumper in the correct location.
The power supply used in the Power Macintosh G3 Desktop is not the same as the power supply used in the Power Macintosh G3 Minitower and Macintosh Server G3 computers.
If the logic board is installed in the Minitower/Server chassis, the power supply jumper must cover the pins marked ÁPSú. If the logic board is installed in the Desktop chassis, this jumper must cover the pins marked ÁMacú. (Replacement logic boards should come preset for the Desktop model.) When replacing the logic board, be sure to check the power supply jumper setting. If this jumper is missing or set incorrectly for the computer model, the computer will fail to boot.
These logic boards include a removable processor module, aka a ZIF (Zero Insertion Force) module. This module can be replaced in the event the stock processor module fails, or to upgrade to a faster processor.
Processor modules are shipped with the appropriate jumper configuration block to place in location J16.
When replacing the processor module, you must change the processor jumper block and warranty sticker to be compatible with the processor module you are installing. Failure to install the jumper block properly will result in a unit that fails to boot.
The voltage regulator module regulates the voltage for the particular processor used in different Power Mac/Server G3 systems. The voltage regulator provides an easy way to regulate voltage without changing specific resistor values on the logic board. When you replace the logic board, you must transfer the voltage regulator from the old logic board to the new one. (Note: Always try replacing the voltage regulator to resolve power-on problems before replacing the logic board.)
Logic Board Revisions
The three logic board revisions discussed in this section 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 slower 233-266MHz G3 processors. The second revision, Rev 2, incorporates a Rage Pro graphics chip, and support for IDE slaves. This revision includes a faster G3 processor running at either 300 or 333 MHz. The third revision to the G3 logic board is the completely 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 450MHz.
Using Apple System Profiler (ASP), located under the Apple menu, you may determine the logic board revision your Macintosh. In Apple System Profiler, click the System Profile tab, then consult the Production Information section. Compare it to the table below to determine your logic board revision.
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 or beige) Power Macintosh G3 300Mhz and 333Mhz Desktop/Minitower computers have revision 2 logic boards.
Master/Slave Configuration Support
Most 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 known as an 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 do not support this feature. This feature is directly related to which logic board revision is present.
A master/slave configuration permits the addition of hard disk drives or removable media drives. Despite the names "master" and "slave", the master drive does not have any special status compared to the slave. They are equal in most respects. Slave drives do not rely on the master drive.
You can install two ATA/IDE devices on the same ATA/IDE channel in a master/slave configuration on these computers:
- Power Mac G4 (PCI and AGP)
- Power Macintosh G3 (Blue and White) (limited to certain configurations)
- Power Macintosh G3 All-in-one
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 work with this feature. Only Power Macintosh G3 Minitower and Desktop computers with a Rev 2 logic board support this feature. You can use the Apple System Profiler application to determine which revision of the logic board is installed in your computer. Alternatively, you may also use Apple System Profiler to determine which ATI Rage graphics accelerator chip is on the logic board. If it is the ATI RAGE PRO chip, the computer has a Rev 2 or later logic board.
Configuring and Connecting
Important: The following information is valid only for Power Macintosh G3 computers that support master and slave configurations.
Each IDE channel can work with either one or two devices. All Power Macintosh G3 computers have two ATA/IDE channels. ATA/IDE devices each contain their own integrated controllers. To maintain order on the channel, it is necessary to have some way of differentiating between the two devices. This is done by giving each device a designation as either master or slave, and then having the controller address commands and data to either device. The drive that is the target of the command responds to it, and the other one remains silent.
Devices are designated as master or slave using jumpers (small connectors that fit over pairs of pins to program the drive). Each hard drive manufacturer uses a different layout of jumpers for specifying whether its drive is master or slave on the channel.
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, 3.3v, SGRAM SO-DIMM 10ns/100MHz|
|Number VRAM Slots||One(1)|
|L2 Cache Supported?||Supports 512K-1MB L2 cache on the backside of the ZIF Processor.|
|DIMM Type||168-pin, 3.3v PC-100 64-bit, 10ns/100Mhz SDRAM.|