Memory Problems - IBM x3950 Problem Determination And Service Manual

Memory problems

v Follow the suggested actions in the order in which they are listed in the Action column until the problem
is solved.
v See Chapter 3, "Parts listing, Type 8878 and 8879," on page 109 to determine which components are
customer replaceable units (CRU) and which components are field replaceable units (FRU).
v If an action step is preceded by "(Trained service technician only)," that step must be performed only by a
trained service technician.
Symptom
The amount of system memory
that is displayed is less than the
amount of installed physical
memory.
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IBM System x3950 Type 8878 and System x3950 E Type 8879: Problem Determination and Service Guide
Action
Note: If you change the memory, you must updated the memory configuration in
the Configuration/Setup Utility program.
1. Make sure that:
v No error LEDs are lit on the operator information panel or on the memory
card.
v Memory mirroring does not account for the discrepancy.
v The memory modules are seated correctly.
v You have installed the correct type of memory.
v 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.
2. Check the POST error log for error message 289:
v If a DIMM was disabled by a system-management interrupt (SMI), replace
the DIMM.
v If a DIMM was disabled by the user or by POST, run the Configuration/Setup
Utility program and enable the DIMM.
3. Run memory diagnostics (see "Running the diagnostic programs" on page 60).
4. Make sure there is no memory mismatch when the server is at the minimum
memory configuration (two 1GB DIMMs; see "Minimum configuration" on page
106).
5. Add one pair of DIMMs at a time, making sure the DIMMs match for each pair
added.
6. Add one memory card at a time, making sure the memory matches for each
card added.
7. Reseat the following components:
a. DIMM
b. Memory card
8. Replace the components listed in step 7 one at a time, in the order shown,
restarting the server each time.