The logic board provides 4 PC-100 DIMM slots, supporting a maximum
of 256 MB per DIMM, for a total of 1 GB.
The logic board uses JEDEC-standard 168 pin SDRAM DIMMs that
are 64-bit bus, non-parity, 168-pin, 3.3-volt, unbuffered, and
PC-100 compliant The speed of the devices must be 100 MHz (8ns).
Note: DIMMs with registers or buffers, DIMMs with PLLs,
and DIMMs with EDO RAM are not supported in the Power Macintosh
G3 computer. The maximum supported height of SDRAM DIMM cards
is 2 inches. The maximum number of devices supported on a DIMM
is 16 SDRAM devices.
There is no memory soldered to the Power Macintosh G3 main logic
board. If all four of the DIMM slots are empty, the computer
will not operate. A single-frequency tone will be generated indicating
that no memory is installed.
The SDRAM DIMMs can be installed one or more at a time. The logic
board supports linear memory organization so no performance gains
are seen when two DIMMs of the same size are installed. Any supported
size DIMM can be installed in any DIMM slot, and the combined
memory of all of the DIMMs installed is configured as a contiguous
array of memory.
You will not be able to re-use DRAM from past Power Macintosh
computers (8500, 8600, PM G3, iMac) in your Power Macintosh G3
(Blue and White).
- Do not use:
- Parity SDRAM DIMMs.
- EDO DIMMs
- ECC (error correcting) SDRAM DIMMs
- Registered or buffered SDRAM
- DIMMs with fewer than 4 or more than 16 devices (irrespective
of any PC-100 sticker or claims)
"PC-100" is an Intel-driven standard for DIMMs compatible
with Intel 100 MHz systems. Intel requires prominent marking
of the DIMM as PC-100, and requires the speed code to be listed
as well. Power Macintosh G3 is compatible with 3-2-3 (slowest),
3-2-2, and 2-2-2 (fastest) speed codes. Power Macintosh G3 will
read the presence detect ROM for information about all the DIMMs
installed in the computer, and set memory timing equal to the
slowest DIMM. Therefore, for maximum performance use only 2-2-2
speed codes. However, the difference in application performance
between the speed codes is small. Power Macintosh G3 typically
ships with a single 3-2-2 DIMM. This may change over time.