From Xojo Documentation

Read-Only Property (As UInt64 )
UInt64Value = aRuntime.MemoryUsed

Supported for all project types and targets.

Returns the total amount of memory used (in bytes) by the allocated objects.


More specifically, this returns the number of malloc'd bytes. Since the OS does not immediately give back memory after it is released there is no guarantee that this number will match OS values that you see in Activity Monitor, Task Manager or top.