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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 resolved:
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.

    • Memory mirrored channel does not account for the discrepancy.

    • The DIMMs are seated correctly.

    • You have installed the correct type of DIMMs.

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

    • All banks of memory are enabled. The server might have automatically disabled a memory bank when it detected a problem, or a memory bank might have been manually disabled.

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

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

  3. Run memory diagnostics. When you start a server and press F1, the Lenovo XClarity Provisioning Manager interface is displayed by default. You can perform memory diagnostics from this interface. From the Diagnostic page, click Run Diagnostic > Memory test.

  4. Check the POST error log:

    • If a DIMM was disabled by a systems-management interrupt (SMI), replace the DIMM.

    • If a DIMM was disabled by the user or by POST, reseat the DIMM; then, run the Setup utility and enable the DIMM.

  5. Reseat the DIMM.

  6. Restart the server.

Multiple rows of DIMMs in a branch identified as failing

  1. Reseat the DIMMs; then, restart the server.
  2. Remove the lowest-numbered DIMM pair 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 lowest-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) Replace the system board.