Lenovo ThinkServer RD650 User Manual
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Note: The memory modules are extremely sensitive to ESD. Ensure that you read and understand “Handling
static-sensitive devices” on page 68 first and carefully perform the operation.
Memory module installation rules
Your server has 24 memory slots and it has the following features:
• Each slot supports 4 GB, 8 GB, and 16 GB double data rate 4 registered dual inline memory modules
(DDR4 RDIMMs) with Error Checking and Correcting (ECC) technology.
• Each slot supports 32 GB double data rate 4 load reduction dual inline memory modules (DDR4
LRDIMMs) with Error Checking and Correcting (ECC) technology.
• Your server supports up to 12 memory modules when one microprocessor is installed. Supports up to 24
memory modules when two microprocessors are installed.
• The minimum system memory is 4 GB (only one microprocessor installed and only one 4 GB RDIMM
installed in the CPU1 DIMMA1 slot).
• The maximum system memory is 768 GB (two microprocessors installed and one 32 GB LRDIMM
installed in each of the 24 memory slots).
For more information about the memory modules in your specific server model, use the Setup Utility
program. See “Viewing information in the Setup Utility program” on page 55.
For a list of the supported ThinkServer memory module options, go to:
Before installing a memory module, ensure that you observe the following guidelines:
• All memory modules to be installed must be the same type. Your server supports the following types
of memory modules:
– DDR4 RDIMM with ECC technology
– DDR4 LRDIMM with ECC technology
• When you install memory modules with different ranks in one channel, start from the farthest memory slot
in the channel. Install the memory module that has the most ranks first.
• When you install memory modules with different frequencies into the memory slots for the same
microprocessor, all the memory modules run at the lowest frequency.
• It is recommended that you install the high-frequency memory modules into the memory slots for the
same microprocessor to ensure high performance.
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