Both ElectricCommander and its private copy of MySQL require a considerable amount of memory. Settings control the amount of memory used. Both settings are "hard" configured at install - that is, they are not adaptive to the capacity of the machine where you are installing Commander.
To increase or decrease Commander memory usage, open the file wrapper.conf in the directory <dataDirectory>/server/conf. Look for these lines:
Adjust both numbers up or down as desired. After saving the changes, stop and restart the Commander Server.
To change the memory usage for the default Commander MySQL database, open the file my.ini in the directory <dataDirectory>/mysql>. Look for the line: innodb_buffer_pool_size=384M
After changing this value, stop the Commander Server and the MySQL database, then restart both.