Service Source Power Mac G5 - Retrocomputing.net

General Information
DDR Memory
In the Power Mac G5, DIMMs must always be installed in pairs of equal size and speed.
Use PC2700 DDR-SDRAM for 4-DIMM-slot computers and PC3200 DDR-SDRAM for
8-DIMM-slot computers. Memory from older Macintosh computers is not compatible. Do
not try to install non-DDR memory as it will not physically fit in the DIMM slots and could
damage the logic board.
Results of Mixing PC2100, PC2700, and PC3200 RAM
The table below describes what happens if you install PC2100, PC2700, or PC3200
memory in either a 4-DIMM-slot or 8-DIMM-slot Power Mac G5 computer.
Four-DIMM-Slot Systems
When only PC2100 DIMMs are
installed
When a mix of PC2100, PC2700, or
PC 3200 DIMMs is installed
When only PC3200 DIMMs are
installed in the slots
When no memory is installed
The computer makes three single tones
instead of the startup sound. The LED on the
front of the computer flashes three times, and
the computer does not startup.
The computer starts up normally, but neither
the computer nor Apple System Profiler
recognizes the PC2100 memory.
The computer starts up normally and behaves
as though PC2700 DIMMs are installed.
The computer does not make a normal startup
sound. Instead, there is a single tone, and the
computer’s front LED flashes continuously.
Eight-DIMM-Slot Systems
When only PC2100 DIMMs are
installed
When a mix of PC2100, PC2700, or
PC 3200 DIMMs is installed
When no memory is installed
The computer makes three single tones
instead of the startup sound. The LED on the
front of the computer flashes three times, and
the computer does not startup.
The computer starts up normally, but neither
the computer nor Apple System Profiler
recognizes the PC2100 memory.
The computer does not make a normal startup
sound. Instead, there is a single tone, and the
computer’s front LED flashes continuously.
General Information
Power Mac G5 Troubleshooting - 1