Dell R805 owner manual System Memory, General Memory Module Installation Guidelines

System Memory

You can upgrade your system memory to a maximum of 128 GB by installing 667-MHz registered parity DDR2 memory modules (DIMMs) in sets of

512-MB, 1-GB, 2-GB, 4-GB, or 8-GB single- or dual-ranked modules (quad- ranked modules are not supported). The memory sockets are located on the system board under the memory module cooling shrouds and are split into two separate groups of eight sockets each. Each eight-socket group is adjacent to its respective processor.

Your system hardware supports Non-Uniform Memory Architecture (NUMA). Each processor has its own memory controller and local memory for reduced access times, but it can also access memory from another processor. This architecture improves system performance if an operating system is installed that supports this feature.

NOTICE: To enable NUMA, run the System Setup program and disable the Node Interleaving option. See "Using the System Setup Program" on page 47.

General Memory Module Installation Guidelines

To ensure optimal performance of your system, observe the following guidelines when configuring your system memory.

•Memory must be installed in configurations of four, eight, or sixteen DIMMs. The minimum configuration is four 512-MB DIMMs.

•DIMMs must be installed in matched sets of identical speed, technology, and size in the following sockets:

–A1, A2, B1, and B2 — four identical DIMMs in this set

–A3, A4, B3, and B4 — four identical DIMMs in this set

–A5 through A8 and B5 through B8 — eight identical DIMMs in this set

•Minimum configurations (four DIMMs) must occupy sockets A1, A2, B1, and B2.

•A matched DIMM set can be mixed with another matched DIMM set of the next smaller size. For example, a DIMM set containing 2-GB DIMMs can be mixed with another DIMM set containing 1-GB DIMMs, but not a set containing 512-MB DIMMs. The larger capacity DIMMs must occupy the lower-numbered DIMM sockets.

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Installing System Components