Dell PowerEdge R415 Hardware Owner's Manual - Page 122

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. • RDIMMs and UDIMMs cannot be mixed. • Except for memory channels that are unused, all populated memory channels must have identical configurations. • In a dual-processor configuration, the memory configuration for each processor must be identical. • Memory modules of different sizes can be mixed in A1-A4 or B1-B4 (for example, 2 GB and 4 GB), but all populated channels must have identical configurations. • For Optimizer Mode, memory modules are installed in the numeric order of the sockets beginning with A1 or B1. • If quad-rank memory modules are mixed with single- or dual-rank modules, the quad-rank modules must be installed in the sockets with the white release levers. • If memory modules with different speeds are installed, they will operate at the speed of the slowest installed memory module(s). Table 3-2, Table 3-3, and Table 3-4 show sample memory configurations that follow the appropriate memory guidelines stated in this section. The samples show identical memory-module configurations and the physical and available memory totals. The tables do not show mixed or quad-rank memory-module configurations, nor do they address the memory speed considerations of any configuration. 122 Installing System Components