all good stuff so far, but virtual memory requirments vary depending upon the system and your needs. I try to have plenty of RAM and hard set virtual memory to a minimum of the same as RAM and maximum of double the RAM.
Reasons for this is that the default setting of 'letting Windows manage your virtual memory' means that it loads a monitoring/management program into your RAM and it stays there all the time, with hard settings this program is NOT loaded, thus giving you more RAM. Whatever the size of your virtual memory the system will set aside some RAM to keep a note off what is in it, the more virtual memory you have the more RAM set aside to track it.
I have seen a system where the suer set the virtual memory so high that there was no RAM left to do anything worthwhile as it was all in use for the virtual memory management.
Switching between applications or data a lot, then you need a lot of virtual memory (and RAM) playing a lot of RAM intensive games then you need less virtual memory. Using CAD and graphics programs usually need more virtual memory unless it is one that has its own settings for 'scratch disk' this is an application specific type of temporary virtual memory that the application sets up and uses so as not to use system virtual memory.