Dell EMC PowerEdge R440 Installation And Service Manual

Table 20. Memory operating modesMemory Operating Mode DescriptionOptimizer Mode The Optimizer Mode if enabled, the DRAM controllersoperate independently in the 64-bit mode and provideoptimized memory performance.Mirror Mode The Mirror Mode if enabled, the system maintains twoidentical copies of data in memory, and the total availablesystem memory is one half of the total installed physicalmemory. Half of the installed memory is used to mirror theactive memory modules. This feature provides maximumreliability and enables the system to continue running evenduring a catastrophic memory failure by switching over to themirrored copy. The installation guidelines to enable MirrorMode require that the memory modules be identical in size,speed, and technology, and they must be populated in sets of6 per processor.Single Rank Spare Mode Single Rank Spare Mode allocates one rank per channel as aspare. If excessive correctable errors occur in a rank orchannel, while the operating system is running, they aremoved to the spare area to prevent errors from causing anuncorrectable failure. Requires two or more ranks to bepopulated in each channel.Multi Rank Spare Mode Multi Rank Spare Mode allocates two ranks per channel as aspare. If excessive correctable errors occur in a rank orchannel, while the operating system is running, they aremoved to the spare area to prevent errors from causing anuncorrectable failure. Requires three or more ranks to bepopulated in each channel.With single rank memory sparing enabled, the systemmemory available to the operating system is reduced by onerank per channel.For example, in a dual-processor configuration with sixteen 16GB dual-rank memory modules, the available system memory:16 GB x 16(memory modules) - 8GB(1 rank sparing/channel) x12(channel) = 256 GB - 96 GB = 160 GB. For multi ranksparing, in a dual-processor configuration with sixteen 64 GBquad-rank memory modules, the available system memory:64 GB x 16(memory modules) - 32 GB(2 rank sparing/channel)x 12 (channel) = 1024 GB - 384 GB = 640 GB.NOTE: To use memory sparing, this feature must beenabled in the BIOS menu of System Setup.NOTE: Memory sparing does not offer protection againsta multi-bit uncorrectable error.Dell Fault Resilient Mode The Dell Fault Resilient Mode if enabled, the BIOS createsan area of memory that is fault resilient. This mode can beused by an OS that supports the feature to load criticalapplications or enables the OS kernel to maximize systemavailability.NOTE: This feature is only supported in Gold and PlatinumIntel processors.NOTE: Memory configuration has to be of same sizeDIMM, speed, and rank.Installing and removing system components 49