Dell PowerEdge R815 Hardware Owner's Manual - Page 93

General Memory Module Installation Guidelines To ensure optimal performance of your system, observe the following general guidelines when configuring your system memory: NOTE: Memory configurations that fail to observe these guidelines can prevent your system from starting and producing any video output. • DIMMs must be populated in matched pairs for each processor (for example, A1/A2, A3/A4). Single DIMM operation is not supported. • All processor memory channels must be populated identically (same speed, size, and type). • The memory configuration for each processor must be identical for optimal performance. • Memory modules must be installed beginning with socket A1 or A2 for processor 1, B1 or B2 for processor 2, and C1 or C2 for processor 3, D1 or D2 for processor 4. • In case of mixed-rank population, first populate the DIMM with the highest number of ranks (in sockets with white release levers). • If memory modules with different speeds are installed, they operate at the speed of the slowest installed memory module(s). • If online sparing is enabled, identical DIMMs must be installed in the same slots across each channel. The system supports advanced ECC, memory interleaving, and online sparing. For information on memory configurations, see Table 3-2 and Table 3-3. Memory Sparing Support Memory sparing is supported in systems that have one of the fully populated memory configurations shown in Table 3-2 and Table 3-3. The memory sparing feature must be enabled in the Memory Settings screen of the System Setup program. See "Using the System Setup Program and UEFI Boot Manager" on page 53. NOTE: The memory sparing and node interleaving features cannot be used at the same time. To use memory sparing, you must disable the Node Interleaving option in the System Setup program. Installing System Components 93