Memory module installation guideline
There are a number of criteria that must be followed when selecting and installing memory modules in your server.
Memory installation requirements:
A label on each DIMM identifies the DIMM type. This information is in the format xxxxx nRxxx PC4-xxxxx-xx-xx-xxx. Where n indicates if the DIMM is single-rank (n=1) or dual-rank (n=2).
At least one DIMM is required for each processor. Install at least six DIMMs per processor for good performance.
The following table includes all the feasible combinations of different types of DIMMs:
Table 1. DIMM compatibility DIMM Types RDIMM LRDIMM 3DS-RDIMM RDIMM V X X LRDIMM X V X 3DS-RDIMM X X V When you replace a DIMM, the server provides automatic DIMM enablement capability without requiring you to use the Setup utility to enable the new DIMM manually.
Mixing x4 and x8 DIMMs in the same channel is allowed.
Install DIMMs of the same speed for optimal performance. Otherwise, the BIOS will find and run the lowest speed among all channels.
Always populate DIMMs with the maximum number of ranks in the farthest DIMM slot, followed by the nearest DIMM slot.