400Mhz DDR vs. 533Mhz DDR2:
Do you have the "Original" G5 that runs 400Mhz DDR memory, or the "Dual Core" G5 that runs 533Mhz DDR2 memory? Refer to our DDR vs. DDR2 Guide.
ECC vs. Non-ECC:
ECC memory is usually used in mission critical applications like servers, but Apple is now making it available to G5 workstations! ECC stands for Error Correction Code. This type of memory uses an extra parity bit to detect and correct some types of memory errors. In order to run ECC, all installed DIMMs must be the ECC type. You can mix ECC and Non-ECC, but the ECC function will be disabled.
The G5 "Dual Core" runs 533Mhz DDR2 memory. These dual core G5s can come with either 1 or 2 processor cards that have two processors on each, and are Dual or Quad G5s. The dual core G5s have 8 memory slots which can each hold a maximum of 2GB, for a system maximum of 16GB.
In order to provide you with optimal performance and stability, all of our G5 kits are configured with matched modules.