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Memory problems

Use this information to resolve issues related to memory.

Displayed system memory is less than installed physical memory​

Complete the following steps until the problem is resolved:
Note
Each time you install or remove a DIMM, you must disconnect the server from the power source; then, wait 10 seconds before restarting the server.
  1. Make sure that:

    • No error LEDs are lit on the operator information panel.

    • No DIMM error LEDs are lit on the system board.

    • Memory mirrored channel does not account for the discrepancy.

    • The memory modules are seated correctly and followed the system memory installation rules.

    • You have installed the correct type of memory.

    • If you changed the memory, you updated the memory configuration in the Setup utility.

    • Check that all banks of memory are enabled in the UEFI setup. The server might have automatically disabled a memory bank when it detected a problem, or a memory bank might have been manually disabled by a previous user.

    • There is no memory mismatch when the server is at the minimum memory configuration.

  2. Reseat the DIMMs, and then restart the server.

  3. Check the POST error log:

    • If a DIMM was disabled by a systems-management interrupt (SMI), move the DIMM to a different slot and run the UEFI setup utility to confirm if the DIMM is enabled, if the DIMM is still disabled then replace the DIMM.

    • If a DIMM was disabled by the user or by POST, move the DIMM to a different slot and run the UEFI setup utility to confirm if the DIMM is enabled, if the DIMM is still disabled then replace the DIMM.

  4. Reverse the DIMMs between the channels (of the same processor), and then restart the server. If the problem is related to a DIMM, replace the failing DIMM.

  5. Re-enable all DIMMs using the Setup utility, and then restart the server.

  6. (Trained technician only) Install the failing DIMM into a DIMM connector for processor 2 (if installed) to verify that the problem is not the processor or the DIMM connector.

  7. (Trained technician only) Replace the system board.

Multiple DIMMs in a channel identified as failing​

Note
Each time you install or remove a DIMM, you must disconnect the server from the power source; then, wait 10 seconds before restarting the server.

  1. Separate each DIMM from the failing channel and install the DIMMs into separate channels (typically the each channel is indicated by a white socket) to isolate the DIMMs; then, restart the server. Replace any of the suspecious DIMMs that fail in new channels.

  2. Remove the highest-numbered DIMM of those that are identified and replace it with an identical known good DIMM; then, restart the server. Repeat as necessary. If the failures continue after all identified DIMMs are replaced, go to step 4.
  3. Return the removed DIMMs, one at a time, to their original connectors, restarting the server after each DIMM, until a DIMM fails. Replace each failing DIMM with an identical known good DIMM, restarting the server after each DIMM replacement. Repeat step 3 until you have tested all removed DIMMs.
  4. Replace the highest-numbered DIMM of those identified; then, restart the server. Repeat as necessary.
  5. Reverse the DIMMs between the channels (of the same processor), and then restart the server. If the problem is related to a DIMM, replace the failing DIMM.
  6. (Trained technician only) Install the failing DIMM into a DIMM connector for processor 2 (if installed) to verify that the problem is not the processor or the DIMM connector.
  7. (Trained technician only) Replace the system board.

DIMM PFA issue​

  1. Update the UEFI and XCC firmware to the latest version.

  2. Reseat the failing DIMMs.

  3. Swap processors and make sure that there are no damages to processor socket pins.

  4. (Train service only) Ensure there is no abnormal material in any DIMM slot.

  5. Run memory diagnostics. When you start a solution and press the key according to the on-screen instructions, the LXPM interface is displayed by default. (For more information, see the “Startup” section in the LXPM documentation compatible with your solution at Lenovo XClarity Provisioning Manager portal page.) You can perform memory diagnostics with this interface. From the Diagnostic page, go to Run Diagnostic > Memory test.

  6. Replace the failing DIMMs that fails Memory Test.