You must replace a DIMM when a memory mismatch is present, or you have a failed DIMM.
Overview and requirements
Before you replace DIMMs, you need to be aware of certain requirements and considerations.
Replace DIMMs
To replace your DIMM you must verify the cache size of your controller, place the controller offline, remove the controller, remove the DIMMs, and install the new DIMMs in your controller. Then you can bring your controller back online and verify the storage array is working properly.