@Strictoaster In your case, Cities.exe has committed 43 GB of memory. Here committed means pretty much the same as allocated.

Of that 43 GB, 39 GB is in active use and kept in RAM. The rest (4 GB) resides somewhere else, as decided by the operating system. In your case, 'somewhere else' is probably not the page file because you have enough RAM.

So, we can guess that the remaining 4 gigabytes are nowhere: it is committed but not yet accessed memory. In virtual memory, reservations are almost free as long as the memory is not accessed. It's like a reservation in the books, waiting to happen.

Thank you for your remarkable work for the user communities!

I think I understand it better now, thanks for the clarification :)