After performing a reboot of a PAM appliance, RAM usage is low, but it starts increasing over time until reaching a percentage of circa 70% after some weeks
Once it is at that figure it does not decrease significantly, even if there is little activity in PAM
This article explains why this behaviour is observed
CA PAM 4.X releases
PAM tries to put unused memory to use. Allocating more memory to MySQL is one of the most effective ways to improve DB performance.
Therefore PAM monitors memory and adjusts MySQL memory, shooting for MySQL to use 60% of overall system memory...
This is retested and adjusted if appropriate every 15 minutes via cron file monitor_and_adjust_system_resources.
Unless memory usage keeps growing, this behaviour is working as designed. Memory usage should be stable around 67-70% after some time of operation due to the mechanism indicated above