Ram consumption

Hi Opigno team. I have an Opigno installation on a 1 GB server and only Opigno is installed and all the modules are running ( i haven't disabled or uninstalled any modules). I like all the features and the way it works etc. However in the monitoring of my server, I find that the available RAM keeps decreasing slowly and steadily. There are no users. There is no data etc. It would be very helpful if someone replied .