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Memory problems

Use this information to resolve issues related to memory.

Displayed system memory less than installed physical memory​

Complete the following steps until the problem is solved.
  1. Make sure that:
    1. You have installed the correct type of memory (see Install a DIMM for instructions).

    2. Memory mirroring or memory sparing mode does not account for the discrepancy.

      To determine the status of a DIMM, restart the server and press the key according to the on-screen instructions to display theLXPM interface. Then, click System settings > Memory.

  2. If new memory has recently been installed, make sure that no configuration events are reported in the event log. If there are any events, resolve them.
    Note
    DIMMs are verified as authentic Lenovo or IBM modules by the UEFI software. If any non-authentic DIMMs are detected, an informational message appears in the system event log and memory performance might be limited. Non-authentic DIMMs are not covered by your Lenovo warranty.
  3. If the compute node was recently installed, moved, or serviced, make sure that the DIMMs are correctly seated in the connectors (see Install a DIMM for instructions).

  4. Make sure that all DIMMs are enabled. The compute node might have automatically disabled a DIMM when it detected a problem, or a DIMM might have been manually disabled.

    To determine the status of a DIMM, restart the server and press the key according to the on-screen instructions to display the LXPM interface. Then, click System settings > Memory.

  5. Run memory diagnostics. When you start a server and press the key according to the on-screen instructions, the LXPM interface is displayed by default. You can perform memory diagnostics from this interface. From the Diagnostic page, click Run Diagnostic > Memory test.

  6. Remove DIMMs until the compute node is showing the correct amount of memory. Install one DIMM at a time until you can determine which DIMM is not working properly. Remove that DIMM and replace it with a good DIMM (see DIMM replacement for instructions).
    Note
    After you install or remove a DIMM, you must change and save the new configuration information by using the Setup utility. When you turn on the compute node, a message indicates that the memory configuration has changed. Press the key according to the on-screen instructions to display the LXPM interface. Then, save the configuration.
  7. If the problem remains, contact Lenovo Support.

Multiple memory modules in a channel identified as failing​

Note
Each time you install or remove a memory module, you must disconnect the solution from the power source; then, wait 10 seconds before restarting the solution.
  1. Reseat the memory modules; then, restart the solution.
  2. Remove the highest-numbered memory module of those that are identified and replace it with an identical known good memory module; then, restart the solution. Repeat as necessary. If the failures continue after all identified memory modules are replaced, go to step 4.
  3. Return the removed memory modules, one at a time, to their original connectors, restarting the solution after each memory module, until a memory module fails. Replace each failing memory module with an identical known good memory module, restarting the solution after each memory module replacement. Repeat step 3 until you have tested all removed memory modules.
  4. Replace the highest-numbered memory module of those identified; then, restart the solution. Repeat as necessary.
  5. Reverse the memory modules between the channels (of the same processor), and then restart the solution. If the problem is related to a memory module, replace the failing memory module.
  6. (Trained technician only) Install the failing memory module into a memory module connector for processor 2 (if installed) to verify that the problem is not the processor or the memory module connector.
  7. (Trained technician only) Replace the system board.