Memory SparingNOTE: To use memory sparing, this feature must be enabled in the System Setup.In this mode, one rank per channel is reserved as a spare. If persistent correctable errors are detected on a rank, thedata from this rank is copied to the spare rank and the failed rank is disabled.With memory sparing enabled, the system memory available to the operating system is reduced by one rank perchannel. For example, in a system with three 8 GB dual-rank DIMMs, the available system memory is: 1/2 (ranks/channel) × 3 (DIMMs) × 8 GB = 12 GB, and not 3 (DIMMs) × 8 GB = 24 GB.NOTE: Memory sparing does not offer protection against a multi-bit uncorrectable error.NOTE: Both Advanced ECC/Lockstep and Optimizer modes support Memory Sparing.Memory MirroringMemory Mirroring offers the strongest DIMM reliability mode compared to all other modes, providing improveduncorrectable multi-bit failure protection. In a mirrored configuration, the total available system memory is one half ofthe total installed physical memory. Half of the installed memory is used to mirror the active DIMMs. In the event of anuncorrectable error, the system will switch over to the mirrored copy. This ensures SDDC and multi-bit protection.Memory installation guidelines:• Memory sockets A1 and A4 are disabled and you can populate DIMMs in memory sockets A2, A3, A5, and A6.• DIMMs installed in memory sockets with white release tabs must be identical and similar rule applies forsockets with black release tabs. For example, DIMMs installed in sockets A1, A2, and A3 must be identical.Sample Memory ConfigurationsThe following table shows sample memory configurations that follow the appropriate memory guidelines stated in thissection.NOTE: 16 GB quad-rank RDIMMs are not supported.NOTE: 1R and 2R in the following table indicates single- and dual-rank DIMMs respectively.Table 1. Memory ConfigurationsSystem Capacity (inGB) DIMM Size (in GB) Number of DIMMs DIMM Rank,Organization, andFrequencyDIMM Slot Population2 2 1 1R, x8, 1333 MT/s, A11R, x8, 1600 MT/s4 2 2 1R, x8, 1333 MT/s, A1, A21R, x8, 1600 MT/s8 2 4 1R, x8, 1333 MT/s, A1, A2, A3, A41R, x8, 1600 MT/s12 4 3 2R, x8, 1333 MT/s, A1, A2, A32R, x8, 1600 MT/s24 8 3 2R, x4, 1333 MT/s, A1, A2, A346
