Increasing Memory Heap
The Java Virtual Machine (JVM) running CLion allocates some predefined amount of memory. The default value depends on the platform. If you are experiencing slowdowns, you may want to increase the memory heap using the corresponding JVM option. See Configuring JVM options for more information.
On the Help menu, click Edit Custom VM Options.
-Xmxoption to a higher value and restart CLion.
CLion also warns you if the amount of free heap memory after a garbage collection is less than 5% of the maximum heap size:
Click Configure to increase the amount of memory allocated by the JVM:
Click Save and Restart and wait for CLion to restart with the new memory heap setting.