For Windows 4D applications you can set the main application memory setting in the System Settings page of the Database Properties dialog:
These settings have two effects:
The block size and the number of blocks allows you to set the maximum amount of memory that will be allocated to the 4D application. When a 4D application is running, it will use as little as necessary, or the entire allocation. However, it will never use more.
The block size sets the size of memory increments that will be allocated to a 4D application as more memory is required.