This article explains how the Launch Scan After Update functionality works for the Anti-Virus component.
The Anti-Virus scanner will enumerate all running processes and find their executables on the disk. Each executable file on the disk is then scanned, and if an infection is found, a real-time scanning alert is generated. This feature is similar to real-time scanning that scans files on disk before they are opened or executed. The difference here is that it is scanning executable files of processes that are already running.
The scanner is not actually scanning the computer's memory per se.
The setting is found in the Advanced Mode window of the F-Secure Policy Manager Console (PMC): F-Secure Anti-Virus > Settings > Virus Definition Updates > Launch Scan After Update.