Like I said before, the amount of memory a VS takes depends entirely on:
- The blades configured for that VS
- The number of connections that VS is configured to support
Obviously there is some other overhead for each VS plus the base OS.
The default setting when you create a VS is 15k connections, which will take far less memory than when you configure it to support, say, 500k.
I know from past experience that a 32bit firewall with 4GB of RAM without VSX can support several hundred thousand connections, again depending on blades configured.
Obviously, if your VS is only configured to supports 15k connections, it will take far less RAM than 4GB.
Again, I'll see if I can get more specific information.