Memory Problems - Lenovo ThinkSystem SD550 V3 User Manual

3. If you are using a USB hub, disconnect the USB device from the hub and connect it directly to the
server.

Memory problems

See this section to resolve issues related to memory.
Common memory problems
• "Multiple memory modules in a channel identified as failing" on page 266
• "Displayed system memory is less than installed physical memory" on page 266
• "Invalid memory population detected" on page 267
Multiple memory modules in a channel identified as failing
Note: Each time you install or remove a memory module, you must disconnect the server from the power
source; then, wait 10 seconds before restarting the server.
Complete the following procedure to solve the problem.
1. Reseat the memory modules; then, restart the server.
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 server. 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 server
after each memory module, until a memory module fails. Replace each failing memory module with an
identical known good memory module, restarting the server 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 server. Repeat as
necessary.
5. Reverse the memory modules between the channels (of the same processor), and then restart the
server. 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 (system board assembly).
Displayed system memory is less than installed physical memory
Complete the following procedure to solve the problem.
Note: Each time you install or remove a memory module, 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. See
• Memory mirrored channel does not account for the discrepancy.
• The memory modules are seated correctly.
• You have installed the correct type of memory module (see
order" on page 47
• After changing or replacing a memory module, memory configuration is updated accordingly 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.
ThinkSystem SD550 V3 User Guide
266
"Troubleshooting by system LEDs and diagnostics display" on page
for requirements).
"Memory module installation rules and
251.