NF8460M4S / NF8465M4S: High Fan Speed from DIMM Placement
Symptom and case diagnosis
Chassis fans ran above 7,000 RPM. The case traced this to DIMMs installed out of order: the DIMM temperature identified as “DIMM JC” in the source could not be read, and the BMC increased fan speed as a protective response. The vendor concluded that the described incident was a placement problem, rather than a failed fan or DIMM.
Motherboard layout
DIMM installation order in the source
The corresponding processor must be installed before its DIMM slots can be used. The source calls for identical DIMM models within the server. After following the service procedure to power off and isolate the server, correct the population using the matching model and processor configuration.
- CPU_0:
P0_DIMM1A / P0_DIMM2A / P0_DIMM3A / P0_DIMM4A / P0_DIMM1B / P0_DIMM2B / P0_DIMM3B / P0_DIMM4B - CPU_1:
P1_DIMM1A / P1_DIMM2A / P1_DIMM3A / P1_DIMM4A / P1_DIMM1B / P1_DIMM2B / P1_DIMM3B / P1_DIMM4B - CPU_2:
P2_DIMM1A / P2_DIMM2A / P2_DIMM3A / P2_DIMM4A / P2_DIMM1B / P2_DIMM2B / P2_DIMM3B / P2_DIMM4B - CPU_3:
P3_DIMM1A / P3_DIMM2A / P3_DIMM3A / P3_DIMM4A / P3_DIMM1B / P3_DIMM2B / P3_DIMM3B / P3_DIMM4B
The source’s general guidance is to distribute DIMMs evenly across installed processors first, then place remaining DIMMs in the supported remaining slots. It repeats this guidance for an odd DIMM count, but one sentence about the remaining slots is incomplete; it does not supply a complete odd-count matrix.
The text also gives a CPU0-only example with one to eight DIMMs in the order above. However, its accompanying population chart explicitly says that only two-CPU and four-CPU configurations are supported. Treat the single-CPU text as an inconsistent source example, not confirmation that a single-CPU configuration is supported on these models. Confirm the actual supported configuration before changing population.
English localization of the source chart. Every dot position is retained. CPU groups 0–3 each use the same pattern; a black dot indicates a populated slot. The chart labels use hyphens while the prose uses underscores for the corresponding slot names.