This reports the total amount of CPU memory physically installed in the switch, expressed in megabytes, a fixed hardware inventory value rather than a live utilization metric. An admin checks this when verifying a switch meets the memory requirements for a particular firmware version or feature set before attempting an upgrade. For example, an older Catalyst 2600 might report only 8 or 16 MB installed, which could be too little to run a newer software image that lists a higher minimum.