These are setting for a sever with a minimum of 16GB of RAM
Make sure no one is on the system.
In pgAdmin select Tools > Server Configuration > postgresql.conf
Review the following 5 settings and make sure each of them has a tick in the box as illustrated below (some of them won't have a tick yet):
After inputting the new values then click on the green Play button (triangle) to update the configuration changes to the config file.
Open Services on the Server and stop the Spire API Service.
Restart the PostgresSQL service.
Start the Spire API Service again.
Test Spire Desktop behaviour.