Installing and removing sled components 57Table 25. Advanced ECC (Lockstep)Processor Configuration Memory population rules Memory population informationSingle CPU Advanced ECC(Lockstep){1,2}, {3,4} Numbers inside the brackets indicatethe slots that must be populated inpairs, odd amount of pairs allowed.Dual CPU Advanced ECC C1{1,2},C2{1,2},C1{3,4},C2{3,4}…. Numbers inside the brackets indicateNOTE: Popu ate (Lockstep)round robinstarting withCPU1the slots that must be populated inpairs, odd amount of pairs allowed.NOTE: Advanced ECC with mirroring is not supported.Memory optimized (independent channel) modeThis mode supports Single Device Data Correction (SDDC) only for memorymodules that use x4 device width. It does not imposeanyspecific slot populationrequirements.Table 26. Memory optimized (independent channel) modeProcessor Configuration Memory population rules Memory populationinformationSingle CPU Optimized (independent 1, 2, 3, 4 Populate in this order,NOTE:Optimizedmodepermits channel)unbalanced configurations, eg, 1:1:1:0odd amount of DIMMsper CPU allowed.DIMM perchannel(DPCDual CPUcombinations.Optimized (independent C1{1}, C2{1}, C1{2}, C2{2}, Populate in this order,NOTE: Populateroundrobinstartingwith channel)CPU1:NOTE: Optimized mode permitsunbalanced configurations, eg, 2:1:1:1 DPCcombinations.Memory mirroringC1{3}, C2{3}… odd amount of DIMMsper CPU allowed.Memory mirroring offers thestrongest memory module reliability mode compared to all other modes, providing improved uncorrectablemulti-bit failure protection. Inamirrored configuration, the total available system memoryis one half of the total installed physicalmemory.Half of the installed memory is used to mirror the active memory modules. In the event of an uncorrectable error, the system switchesover to the mirrored copy. This ensures SDDC and multi-bit protection.The installation guidelines for memory modules are as follows:• Memory modules must be identical in size, speed, and technology.• DIMMsinstalledinmemorysockets with whitereleasetabsmust beidenticalandsimilarrule appliesforsockets with blackreleasetabs.This ensures that identical DIMMs are installed in matched pairs—for example, A1 with A2, A3 with A4.NOTE: Mirroring and Advanced ECC modes require minimum of two DIMMs per CPU and must be populated in pairs of eithertwoor four DIMMs per CPU.
