Dell PowerEdge R910 Hardware Owner's Manual - Page 92

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. • All populated memory risers must have identical configurations. • The memory configuration for each processor must be identical for optimal performance. • Memory modules of different sizes can be mixed (for example, 2 GB and 4 GB), but all populated channels must have identical configurations. The mixed memory configurations must be of the size N+/-1. • The memory speed depends on the processor bin. • 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 operate at the speed of the slowest installed memory module(s). The memory speeds are also dependent on the processor bin. Two memory risers are allocated to each processor. The number of channels used and the allowable configurations depend on the memory mode selected. The system supports memory mirroring if identical memory modules are installed in both the risers. Mirroring must be enabled in the System Setup program. In a mirrored configuration, the total available system memory is one-half of the total installed physical memory. NOTE: Memory sparing and mirroring are enabled only when memory configurations are greater than or equal to 64 GB. 92 Installing System Components