RAM Expansion
The main logic board has four DDR SDRAM expansion slots for dual in-line memory modules (DIMMs). Each DIMM can contain 256 and 512 MB (also is 128 MB- and 1GB-capable) of double data rate synchronous dynamic RAM (DDR SDRAM). At least one of the RAM expansion slots contains a factory installed DIMM.
The DIMMs can be installed one or more at a time. The system supports linear memory organization; 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.
The memory slots will accept four 512-MB DIMMs (also is capable of 2-1GB) for a maximum memory size of 2 GB.
For all microprocessor speeds and for both DDR226 and DDR333 SDRAM DIMMs, the Power Mac G4 supports CAS latencies of 2, 2.5, 3, 3.5, and 4.