In MoriaServerConfig.ini, you can set the FPS limit of the server or adjust the LoadedAreaLimit. We suggest FPS 60. Higher values are unlikely to improve the server performance. However if your server uses too much CPU, you might try 30 fps instead.
For the LoadedAreaLimit, set a number between 4 and 32 for the maximum number of areas to keep loaded at once. The default is 12 loaded areas, which generally supports 8 player sessions well. If you wish to improve performance, reducing to 8 loaded areas supports 4 player sessions very well. Increasing this number above 12 may decrease the number of loading walls you see, at the cost of much higher memory and CPU usage, as more enemies will need to be simulated to fill those areas.