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Memory module installation

The following notes describe the types of DIMMs that the server supports and other information that you must consider when you install DIMMs.

  • When you install or remove DIMMs, the server configuration information changes. When you restart the server, the system displays a message that indicates that the memory configuration has changed.
  • The server supports only industry-standard double-data-rate 3 (DDR3), 800, 1066, 1333, 1600, or 1866 MHz, PC3-6400, PC3-8500, PC3-10600, PC3-12800, or PC3-14900 registered or unbuffered, synchronous dynamic random-access memory (SDRAM) dual inline memory modules (DIMMs) with error correcting code (ECC). See the Lenovo ServerProven website for a list of supported memory modules for the server.
    • The specifications of a DDR3 DIMM are on a label on the DIMM, in the following format.
    • gggggeRxff PC3v-wwwwwm-aa-bb-ccd
      where:
      • ggggg is the total capacity of the DIMM (for example, 1GB, 2GB, or 4GB)
      • eR is the number of ranks
        • 1R = single-rank
        • 2R = dual-rank
        • 4R = quad-rank
      • xff is the device organization (bit width)
        • x4 = x4 organization (4 DQ lines per SDRAM)
        • x8 = x8 organization
        • x16 = x16 organization
      • v is the SDRAM and support component supply voltage (VDD)
        • Blank = 1.5 V specified
        • L = 1.35 V specified, 1.5 V operable
          Note
          Values for these voltages are ‘specified’ which means the device characteristics such as timing are supported at this voltage. Values are ‘operable’ which means that the devices can be operated safely at this voltage. However, device characteristics such as timing may not be guaranteed. All devices must be ‘tolerant’ of the highest DDR3 nominal voltage of 1.5 V, meaning that they may not operate at 1.5 V but may be powered at that voltage without damage to the devices.
        • wwwww is the DIMM bandwidth, in MBps
          • 6400 = 6.40 GBps (DDR3-800 SDRAMs, 8-byte primary data bus)
          • 8500 = 8.53 GBps (DDR3-1066 SDRAMs, 8-byte primary data bus)
          • 10600 = 10.66 GBps (DDR3-1333 SDRAMs, 8-byte primary data bus)
          • 12800 = 12.80 GBps (DDR3-1600 SDRAMs, 8-byte primary data bus)
          • 14900 = 14.93 GBps (DDR3-1866 SDRAMs, 8-byte primary data bus)
        • m is the DIMM type
          • E = Unbuffered DIMM (UDIMM) with ECC (x72-bit module data bus)
          • L = Load Reduction DIMM (LRDIMM)
          • R = Registered DIMM (RDIMM)
          • U = Unbuffered DIMM with no ECC (x64-bit primary data bus)
        • aa is the CAS latency, in clocks at maximum operating frequency
        • bb is the JEDEC SPD Revision Encoding and Additions level
        • cc is the reference design file for the design of the DIMM
        • d is the revision number of the reference design of the DIMM
      Note
      To determine the type of a DIMM, see the label on the DIMM. The information on the label is in the format xxxxx nRxxx PC3v-xxxxxx-xx-xx-xxx. The numeral in the sixth numerical position indicates whether the DIMM is single-rank (n=1), dual-rank (n=2), or quad-rank (n=4).
  • The following rules apply to DDR3 RDIMM speed as it relates to the number of RDIMMs in a channel:
    • When you install 1 RDIMM per channel, the memory runs at 1866 MHz
    • When you install 2 RDIMMs per channel, the memory runs at 1600 MHz
    • When you install 3 RDIMMs per channel, the memory runs at 1066 MHz
    • All channels in a server run at the fastest common frequency
    • Do not install registered, unbuffered, and load reduction DIMMs in the same server
  • The maximum memory speed is determined by the combination of the microprocessor, DIMM speed, DIMM type, Operating Modes in UEFI settings, and the number of DIMMs installed in each channel.
  • In two-DIMM-per-channel configuration, a server with an Intel Xeon™ E5-2600 series microprocessor automatically operates with a maximum memory speed of up to 1600 MHz when the following condition is met:
    • Two 1.35 V single-rank, dual-rank, or quad-rank UDIMMs, RDIMMs or LRDIMMs are installed in the same channel. In the Setup utility, Memory speed is set to Max performance and LV-DIMM power is set to Enhance performance mode. The 1.35 V UDIMMs, RDIMMs or LRDIMMs will function at 1.5 V.
  • The server supports a maximum of 16 dual-rank UDIMMs. The server supports up to two UDIMMs per channel.
  • The server supports a maximum of 24 single-rank, dual-rank, or 16 quad-rank RDIMMs. The server does not support three quad-rank RDIMMs in the same channel.
  • The following table shows an example of the maximum amount of memory that you can install using ranked DIMMs:
    Table 1. Maximum memory installation using ranked DIMMs.

    Four column table for documenting the number of DIMMs, DIMM type, DIMM size, and total memory.

    Number of DIMMsDIMM typeDIMM sizeTotal memory
    16Single-rank UDIMMs2 GB32 GB
    24Single-rank RDIMMs2 GB48 GB
    24Single-rank RDIMMs4 GB96 GB
    24Dual-rank RDIMMs8 GB192 GB
    24Dual-rank RDIMMs16 GB384 GB
    16Quad-rank RDIMMs16 GB256 GB
    24Quad-rank LRDIMMs32 GB768 GB
  • The UDIMM option that is available for the server is 2 GB. The server supports a minimum of 2GB and a maximum of 32 GB of system memory using UDIMMs.
  • The RDIMM options that are available for the server are 2 GB, 4 GB, 8 GB, and 16 GB. The server supports a minimum of 2 GB and a maximum of 384 GB of system memory using RDIMMs.
  • The LRDIMM option that is available for the server is 32 GB. The server supports a minimum of 32 GB and a maximum of 768 GB of system memory using LRDIMMs.
    Note
    The amount of usable memory is reduced depending on the system configuration. A certain amount of memory must be reserved for system resources. To view the total amount of installed memory and the amount of configured memory, run the Setup utility. For additional information, see Configuring the server.
  • A minimum of one DIMM must be installed for each microprocessor. For example, you must install a minimum of two DIMMs if the server has two microprocessors installed. However, to improve system performance, install a minimum of four DIMMs for each microprocessor.
  • DIMMs in the server must be the same type (RDIMM, UDIMM, or LRDIMM) to ensure that the server will operate correctly.
  • When you install one quad-rank DIMM in a channel, install it in the DIMM connector furthest away from the microprocessor.
  • For UDIMMs, DIMM connectors 3, 6, 7, and 10 for microprocessor 1 and DIMM connectors 15, 18, 19, and 22 for microprocessor 2 are not used.
Note
You can install DIMMs for microprocessor 2 as soon as you install microprocessor 2; you do not have to wait until all of the DIMM slots for microprocessor 1 are filled.

The following illustration shows the location of the DIMM connectors on they system board.

Figure 1. The location of the DIMM connectors on the system board
The location of the DIMM connectors on the system board
  • DIMM installation sequence
    Depending on the server model, the server may come with a minimum of one 2 GB or 4 GB DIMM installed in slot 1. When you install additional DIMMs, install them in the order shown in the following table to optimize system performance.
  • Memory mirrored channel
    Memory mirrored channel mode replicates and stores data on two pairs of DIMMs within two channels simultaneously. If a failure occurs, the memory controller switches from the primary pair of memory DIMMs to the backup pair of DIMMs.
  • Memory rank sparing
    Sparing enables a failing rank to be replaced by ranks installed in an unoccupied space. An unused spare rank on the channel can be used to copy the contents of a failing rank on that channel.
  • Installing a DIMM
    Use this information to install a DIMM.
  • Installing a DIMM
    Use this information to install a DIMM.