There are two scenarios in which you are required to populate DIMMs:
A DIMM fails and needs to be replaced.
In this scenario, you can use the Fault Remind button to identify the failed DIMM, then remove the failed DIMM and replace it. To ensure that system performance is maintained, you must replace the failed DIMM with a DIMM of the same size (in gigabytes) and type 64-GB quad-rank (QR) Load-Reduced DIMMs (LRDIMMs). In this scenario, you should not change the DIMM configuration.
You have purchased new DIMMs and you want to use them to upgrade the server's memory.
In this scenario, you should adhere to DIMM population rules. See DIMM Population Rules.