Physical Memory vs. Virtual Memory

[Dj64Mk7]

This is something that's confused me for a long time.

What is the difference between physical memory and virtual memory? Obviously, physical memory is the literal stick(s) of memory in our Macs.

Virtual memory, however, is what confuses me. For example, I have 8GB of physical memory in my Mac. Activity Monitor says I also have 8GB of virtual memory. Does this mean that I essentially have 16GB of RAM? Or is virtual memory just another term for swap?

 

[Weaselboy]

Does this mean that I essentially have 16GB of RAM? Or is virtual memory just another term for swap?

This right here. It is just swap space on the drive used as temp memory storage.

 

[Dj64Mk7]

This right here. It is just swap space on the drive used as temp memory storage.

Then why does Activity Monitor make the distinction between the two, like in the attached screenshot?

 

[chown33]

Then why does Activity Monitor make the distinction between the two, like in the attached screenshot?

One reasons is that virtual memory can be larger than physical memory.

In theory, virtual memory can be smaller than physical memory, too, but there's no practical reason for doing that here.

 

[poiihy]

Virtual Memory is the combination of Physical Memory and swap space. It will always initially equal your physical RAM, but it grows as your system prepares swap space.

 

[Dj64Mk7]

Virtual Memory is the combination of Physical Memory and swap space. It will always initially equal your physical RAM, but it grows as your system prepares swap space.

Basically V=P+S because swap is added to physical memory when it runs out.
That makes sense, thanks.