there is no way to "predict" the performance.
If you really want to know before deploying, you will need to put your csm config under stress in a lab.
Information to monitor are
'sho mod csm X tech util'
Check IXP CPU utilisation and available memory.
Also, get a 'sho mod csm X stats' and make sure the number of "Connections Current" is lower than the max 1 million.
Gilles.