JetBrains IDE displays a different memory value in the status bar compared to the value set through "Help | Change Memory Settings" or the -Xmx JVM flag

Situation

After configuring the Maximum Heap Size like 4096 via the JetBrains IDE's main menu Help | Change Memory Settings or by adjusting -Xmx in Help | Edit Custom VM Options , the memory indicator in the status bar uses a different value, such as 845 of 3600MB.

Answer

The Heap -> Max represents the Maximum Heap Size/Xmx set in the IDE.

The IDE can allocate a heap size less than the Maximum Heap Size when using and increasing the allocation only when needed.

In the example picture case, the IDE allocates approximately 2352 MB of memory from the OS for heap memory. It reports 3600 MB for Heap Committed + ByteBuffers (direct) + JVM. (The memory displayed in Task Manager or Activity Monitor may actually be higher than this value).

The memory indicator in the status bar displays a purple section to show the current heap usage (845 MB) and a gray section to indicate the committed heap size allocated by the IDE.

For further details on the differences between Heap Used, Committed, and Max, refer to the documentation here.