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 determine the failed DIMM, and 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 (quad-rank). In this scenario, do not change the DIMM configuration.
You purchased new DIMMs and you want to use them to upgrade the server's memory.
In this scenario, adhere to the DIMM population rules. See DIMM Population Rules.