If your logic is right, then I should be able to run a handful of apps and it shouldn't cause page out.
Just to satisfy you, I just cold booted.
- Launch Terminal and type "vm_stat" to observe "Pageouts: 0"
- Launch iTunes, Mail, Messages, and Safari
- Open Gmail, Google Maps, NY Times, and TheVerge in Safari tabs.
- Type "vm_stat" in terminal to observe "Pageouts: 7976"
That still doesn't necessarily mean your performance is degraded or that you would benefit from more memory.
The memory management done by the operating system is a balancing act between many different variables.
The goal is that if there is a demand on memory, that enough memory is available to meet that demand quickly.
So if an app allocates some memory, it should be able to do so from a pool of physical memory that is already allocated to it. So the OS has to essentially guess how much memory each app might want to allocate in the near future.
And if the user wants to run a new app, there should be enough free physical memory to do so without paging. So the OS also has to guess how big an app you might want to run in the near future.
To free up physical memory to satisfy both of these goals, the OS can preemptively compress and/or swap out pages of memory that are infrequently used or not used at all. OS X does this in the background with minimal impact on performance.
So when you see that something has been paged out, that doesn't necessarily mean your machine ran out of memory and was running slower than optimally at any point.
It could very well mean that OS X thinks you would benefit from having more available physical memory vs. having that memory occupied by pages of data that are infrequently (or never) accessed.
Admittedly this is a memory management strategy that has been made possible recently by multi-core CPUs that can compress memory in the background with no practical impact to performance and SSDs which can swap memory out without needing to "spin up" or make annoying seek noises, so maybe that's why people aren't very familiar with it yet.
The critical question is, if you look at the "memory pressure" graph in Activity Monitor, is it green? If it's green, the OS "thinks" there's enough physical memory available for the computer to satisfy reasonable requests of it in the near future.