Chapter 4. IBM NeXtScale nx360 M4 compute node 73The following memory protection technologies are supported: ECC Chipkill (for x4-based memory DIMMs; look for “x4” in the DIMM description;for x8-based memory DIMMs, only ECC protection is supported) Memory mirroring mode Memory lock-step modeWhen mirrored mode is used, DIMM 1 and DIMM 2 hold the same data forredundancy purposes. If one DIMM fails, it is disabled and the backup DIMM inthe other channel takes over. Likewise, DIMM 3 and DIMM 4 hold the same dataand create a mirrored pair. Because memory mirroring is handled in hardware, itis operating system-independent. The total usable memory size is half the total ofthe installed memory.Lock-step mode requires paired memory channels (DIMM 1 and DIMM 2,DIMM 3 and DIMM 4) to be populated by the same memory regards the size andthe organization. Lock-step mode allows Single Device Data Correction (SDDC)memory protection for x8-based memory DIMMs.4.6.1 DIMM installation orderThe IBM NeXtScale nx360 M4 boots with only one memory DIMM installed perprocessor. However, the suggested memory configuration is to balance thememory across all the memory channels on each processor to use the availablememory bandwidth. For best performance, it is recommended to populate allDIMM slots.00D5036 A3QH 8GB (1x8GB, 1Rx4, 1.35V) PC3L-12800CL11 ECC DDR3 1600MHz LP RDIMM8 -00D5044 A3QK 8GB (1x8 GB, 2Rx8, 1.35 V) PC3L-12800CL11 ECC DDR3 1600MHz LP RDIMM8 -46W0672 A3QM 16GB (1x16GB, 2Rx4, 1.35V) PC3L-12800CL11 ECC DDR3 1600MHz LP RDIMM8 -LRDIMMs46W0761 A47K 32GB (1x32GB, 4Rx4, 1.5V) PC3-14900CL13 ECC DDR3 1866MHz LP LRDIMM8 -PartnumberFeaturecodeDescription MaximumsupportedModelswhere used
