IBM 71413SU - System x3950 M2 Reference

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28 IBM System x3950 M2 and x3850 M2 Technical IntroductionThe requirements are as follows: Operating system support: Adding usable system memory to a running operating systemrequires operating system support. This is done with an ACPI sequence. Currently, theonly operating system that has this capability and is supported on the x3850 M2 andx3950 M2 is Windows Server 2003, Enterprise Edition or Datacenter Edition. Memory hot-add must be specifically enabled in the BIOS setup. When this is done, thesystem allocates blank windows of memory space for future memory additions. Byenabling hot-add, memory mirroring will automatically be disabled. Memory cards 2 and 4 must not be installed yet because these are the only ones that canbe hot-added. If only one memory card, memory card 1, is installed prior to the hot-add operation, thenonly one additional memory card may be added in slot 2. If two memory cards are installed in slots 1 and 3, then two additional memory cards canbe added in slots 2 and 4. The DIMMs must be add in matched pairs, that is, two at a time, and they must also matchthe equivalent pair of DIMMs on the matching memory card on the other power bus. A minimum of 4 GB of memory must be installed in the server for hot-add memory to beavailable. Additionally, for 32-bit operating systems, the Physical Address Extension(PAE) mode has to be enabled to take advantage of the additional memory.For information about how to perform a hot-add operation, and more information about therestrictions, refer to x3850 M2 and x3950 M2 User’s Guide.Memory configuration in BIOSConfigure the memory subsystem in the server’s BIOS Setup menu by clicking AdvancedSettings -> Memory Settings -> Memory Array Setting. The choices are listed in Table 11.Table 11 Memory configuration modes in BIOSNote: As previously mentioned, hot-add and hot-swap are mutually exclusive. You canonly enable one of these features.Note: Observe the following concepts when hot-adding memory. If you plan to enable hot-add memory and you have a x3850 M2 and x3950 M2 systemthat comes standard with two memory cards, you need to move memory card 2 to slot 3to be able to hot-add memory cards in slots 2 and 4. After you have added a memory card with two DIMMs, you cannot add more memory tothat same memory card without powering off the server. Enabling hot-add reserves a portion of the memory map for the memory that can behot-added in the future. If you do not plan to use hot-add, we recommend that you donot enable this feature in BIOS.Mode MemoryProteXionMemory-mirroringHot-swapmemoryHot-addmemoryHPMA (high performance memory array) Yes Disabled Disabled DisabledFAMM (full array memory mirroring) Yes Yes Yes DisabledHAM (hot-add memory) Yes Disabled Disabled Yes