Installing a memory module

The following notes describe the types of dual inline memory modules (DIMMs) that the server supports and other information that you must consider when you install DIMMs (see Compute book for the location of the DIMM connectors):

• Confirm that the server supports the DIMM that you are installing (see the Lenovo ServerProven website).
• 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. You can use the Setup utility to view the server configuration information, see Using the Setup utility for more information.
• Server models with the DDR3 compute book support error correcting code (ECC) for up to 96 industry-standard PC3-12800R 1600 MHz, PC3L-12800 1600 MHz or PC3L-10600 1333 MHz Load Reduced (LR), single-rank, dual-rank, or quad-rank, DDR3 (third-generation double-data-rate), registered, synchronous dynamic random access memory (SDRAM) DIMMs.
• Server models with the DDR4 compute book support error correcting code (ECC) for up to 96 industry-standard PC4-17000 2400 MHz, single rank x4, dual rank x4, quad rank x4, single rank x8, dual rank x8, and quad rank x8 RDIMM configurations, DDR4 (fourth-generation double-data-rate), registered, synchronous dynamic random access memory (SDRAM) DIMMs.
• The server also supports 200 GB and 400 GB eXFlash DIMMs. You can use eXFlash DIMMs to utilize unused DIMM slots to increase high performance storage capabilities. You can use eXFlash DIMMs as block storage or storage cache. For additional information about eXFlash DIMM installation and requirements, see eXFlash DIMMs. For more information about supported eXFlash DIMMs, see Table 3.
• You use the same installation procedure to remove or install eXFlash DIMMs as you do to remove and install the other DIMMs in the server.
• Higher capacity (ranked) DIMMs must be installed first. Follow the population sequence for the appropriate mode.
• The server supports a maximum of 8 ranks (octal-rank) per DDR3 or DDR4 channel.
  Note

  LR-DIMMs might exceed 8 ranks per channel through rank multiplication.
• Do not mix RDIMMs and LR-DIMMs in the same server.
• The server supports the following DDR3 DIMMs:

  Table 1. Supported DDR3 DIMMs

  Capacity	Density	Ranks	Organization	Form factor	Voltage	Type	Bandwidth (MHz)
  4 GB	2 Gb	1R	512Mb x4	Low profile	1.35V	RDIMM	1600 MHz
  8 GB	4 Gb	1R	1024Mb x4	Low profile	1.35V	RDIMM	1600 MHz
  16 GB	4 Gb	2R	1024Mb x4	Low profile	1.35V	RDIMM	1600 MHz
  32 GB	4 Gb	4R	1024Mb x4	Low profile	1.35V	LR-DIMM	1600 MHz
  64 GB	4 Gb	8R	1024Mb x4	Low profile	1.35V	LR-DIMM	1333 MHz

• The server supports the following DDR4 DIMMs:

  Table 2. Supported DDR4 DIMMs

  Capacity	Density	Ranks	Organization	Form factor	Voltage	Type	Bandwidth (MHz)
  8 GB	4 Gb	1R	1024Mb x4	Low profile	1.2V	RDIMM	2133 MHz
  8 GB	4 Gb	1R	1024Mb x4	Low profile	1.2V	RDIMM	2400 MHz
  16 GB	4 Gb	2R	1024Mb x4	Low profile	1.2V	RDIMM	2133 MHz
  16 GB	4 Gb	2R	1024Mb x4	Low profile	1.2V	RDIMM	2400 MHz
  32 GB	8 Gb	2R	2048Mb x4	Low profile	1.2V	RDIMM	2133 MHz
  32 GB	8 Gb	2R	2048Mb x4	Low profile	1.2V	RDIMM	2400 MHz
  64 GB	8 Gb	4R	2048Mb x4	Low profile	1.2V	LR-DIMM	2133 MHz
  64 GB	8 Gb	4R	2048Mb x4	Low profile	1.2V	LR-DIMM	2400 MHz
  128 GB	8 Gb	8R	2048Mb x4	Low profile	1.2V	3DS RDIMM	2400 MHz

  Note

  Considerations when installing 128 GB TruDDR4 Memory (8Rx4 1.2V) PC4-2400-R 2400MHz 3DS RDIMMs:

  • These DIMMs are supported only in systems that have E7-4xxx or E7-8xxx processors installed.

  • Installing any other type of DIMM in the same system as the 128 GB RDIMM is not supported.

  • The system must be running UEFI vcersion 4.10 (build ID A9E140J) or higher.

• The server supports the following eXFlash DDR3 DIMMs:

  Table 3. Supported eXFlash DDR3 DIMMs

  Storage	SDRAM Equivalent Capacity	SDRAM Equivalent Density	SDRAM Equivalent Ranks	SDRAM Equivalent Organization	Form factor	Voltage	Type	Bandwidth (MHz)
  200 GB eXFlash DIMM	8 GB	4 Gb	1R	1024Mb x 4	DDR3 low profile	1.35V	RDIMM	1600 MHz
  400 GB eXFlash DIMM	8 GB	4 Gb	1R	1024Mb x4	DDR3 low profile	1.35V	RDIMM	1600 MHz

• Server models with the DDR3 compute book support 1.35-volt (low-voltage) registered DIMMs, depending on the memory configuration settings in the Setup utility, it can also operate at 1.5-volt.
• Server models with the DDR4 compute book support 1.2-volt (low-voltage) registered DIMMs, depending on the memory configuration settings in the Setup utility, it can also operate at 1.5-volt.
• Each compute book has four memory channels, eight DDR3 or DDR4 channels (two DDR3 or DDR4 channels per memory channel), and each DDR3 or DDR4 channel supports three DIMMs as shown in the following illustration:
  
  
  
• When you replace a DIMM, the server provides automatic DIMM enablement capability without requiring you to use the Setup utility to enable the new DIMM manually.
• The maximum operating speed of the server is determined by the slowest DIMM in the server.
• A minimum of one DIMM must be installed for each compute book. For example, you must install a minimum of two DIMMs if the server has two compute books (one in each compute book). If you install four compute books in the server, you must install a minimum of four DIMMs (one DIMM in each compute book).
  Note

  • When one DIMM per compute book is installed, system performance can be slow.
  • For best performance, install DIMMs evenly across all four memory channels for each compute book.
• The server supports two operating modes, independent memory mode and lockstep memory mode. Both modes support memory-mirroring and memory rank sparing. For more information about memory mirroring, see Memory mirroring. For more information about memory rank sparing, see Memory rank sparing.
  • Independent memory mode: This mode provides the most efficient performance. It supports single-device data correction (SDDC) for x4 SDRAM technology. All cache lines are handled on an individual basis by the memory controller. Each DDR3 or DDR4 channel provides 8 x 8 byte data transfers (64 byte cache line is provided per channel). For more information on the independent memory mode, see Independent memory mode.
  • Lockstep memory mode: This mode provides the best memory RAS features. It supports dual-device data correction (DDDC) for x4 SDRAM technology. The memory controller handles all cache lines across the two DDR3 or DDR4 channels (Channel 0 and Channel 1) on each memory channel. Each DDR3 or DDR4 channel provides 4 x 8 byte data transfers (64 byte cache line is provided per channel pair). For more information about the lockstep memory mode, see Lockstep memory mode.

For more information and DIMM population sequence for independent memory mode, see Memory mirroring in independent memory mode and Memory rank sparing in independent mode. For more information and DIMM population sequence for lockstep memory mode, see Memory mirroring in lockstep mode and Memory rank sparing in lockstep mode.