What exactly does Activity Monitor's Memory column mean?
How come in the example situation below (from a macOS High Sierra system) the Real Mem column is greater than the Memory column?
According to a previous question How is the "Memory" column calculated in Activity Monitor?, one might expect that Real Mem should always be less than or equal to Memory, which apparently is not always true.
Edit: This behavior is not only applicable for the kernel task but also to other processes. For example, in the screenshot below we see a couple Google Chrome Helpers experiencing the same behavior, where Real Mem > Memory. The same can be seen with Dock, Notes, Spotlight, Facetime.