Dell Poweredge R440 Specifications

Memory Modes for the Dell Poweredge R440.

The Optimizer Mode, when enabled, allows DRAM controllers to operate independently in 64-bit mode and deliver enhanced memory performance. On the other hand, when the Mirror Mode is enabled, two copies of data will be created in the system memory, thereby cutting the available memory in half. The Mirror Mode ensures maximum reliability and prevents catastrophic memory failures by switching to the mirrored copy. To use this mode, the memory modules need to be identical in size, speed, and technology, and they must be configured in sets of 6 per processor.
In Single Rank Spare Mode, one rank per channel is allocated as a spare. If excessive correctable errors are detected in a rank or channel, they are moved to the spare area to prevent errors from causing an uncorrectable failure. To enable this mode, two or more ranks must be populated in each channel. For Multi Rank Spare Mode, two ranks per channel are allocated as a spare. As such, excessive correctable errors are moved to the spare area to prevent them from leading to an uncorrectable failure. In this case, three or more ranks must be populated in each channel.
For Single Rank Sparing, the system memory available to the operating system will be reduced by one rank per channel. As an example, a dual-processor configuration with sixteen 16 GB dual-rank memory modules would yield an available system memory of 256 GB - 96 GB = 160 GB. When utilizing Multi Rank Sparing in a dual-processor configuration with sixteen 64 GB quad-rank memory modules, the available system memory would be 1024 GB - 384 GB = 640 GB.
Additionally, Dell Fault Resilient Mode must be enabled in the BIOS menu of System Setup. With this feature, an area of memory is made fault-resistant, which allows the OS to maximize system availability by loading critical applications. Note that memory sparing does not offer protection against a multi-bit uncorrectable error.