Memory problemsSee this section to resolve issues related to memory.Common memory problems• “Displayed system memory is less than installed physical memory” on page 220• “Invalid memory population detected” on page 220• “DIMM PFA issue” on page 220Displayed system memory is less than installed physical memoryComplete the following procedure to solve the problem.Note: Each time you install or remove a memory module, you must disconnect the server from the powersource.1. See “Memory module installation rules and order” on page 44 to make sure that the present memorymodule population sequence is supported and you have installed the correct type of memory module.2. Check whether any DIMM error LED is lit on the processor board and whether any memory module isnot displayed in Setup Utility. If yes, check the customer/L1 actions by following the error eventtriggered in XCC or UEFI.3. If the problem persists, replace the failing memory module with one that functions well.• If the new memory module still functions well, it indicates that the original memory module isdamaged. In this case, replace the memory module with a good one.• If the new memory module cannot function well, it indicates that the memory slot is damaged. In thiscase, replace the processor board (trained technician only).• There are few cases in which the memory error is relative to processors. Replace the affectedprocessors if the above actions does not help on customer’s situation (trained technician only).4. Run the memory module diagnostics. When you start a server and press the key according to the on-screen instructions, the Lenovo XClarity Provisioning Manager interface is displayed by default. Fromthe Diagnostic page, click Run Diagnostic ➙ Memory Test ➙ Advanced Memory Test. If any memorymodule fails the test, repeat steps 2 and 3.Invalid memory population detectedIf this warning message appears, complete the following steps:Invalid memory population (unsupported DIMM population) detected. Please verify memory configuration is valid.1. See “Memory module installation rules and order” on page 44 to make sure the present memory modulepopulation sequence is supported.2. If the present sequence is indeed supported, see if any of the modules is displayed as “disabled” inSetup Utility.3. Reseat the module that is displayed as “disabled,” and reboot the system.4. If the problem persists, replace the memory module.DIMM PFA issue1. Update the UEFI and XCC firmware to the latest version.2. Reseat the failing memory modules.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 memory module slot.220 ThinkSystem SR665 V3 User Guide