Xserve Memory for Model 2,1 (Early 2008)

The Xserve 2,1 is based on the Intel Xeon 5400 series CPU.  The Xserve 2,1 uses fully buffered memory, also known as an FB-DIMM. There are eight (8) slots, and the FB-DIMMs must be installed in pairs (2x at a time).  To run 256 Bit Addressing they would be installed in matched quads (4x identical modules). The original 1GB module is installed as a pair of two 512MB FB-DIMMs. The system maximum is 32GB with the installation of eight (8) 4GB FB-DIMMs.

Matched Modules: Ramjet kits contain a matched pair of FB-DIMMs. The kit will consist of identical brand/model/spec IC's. They will be from a single batch, and will have matching series numbers. This ensures perfect compatibility.

256 Bit Addressing: The Xserve 2,1 is capable of addressing a bank of four (4) FB-DIMMs as a single 256-bit memory bus. Having your memory installed as a matched quad will increase your system performance by 5-10%. The Ramjet 1GB FB-DIMM kit (2x 512mb) can be installed along with the Apple original 1GB (2x 512mb) to create a 256 bit quad of four (4) 512MB FB-DIMMs.

Please view Apple's installation guide for more information.
Apple's installation guide.