May be rohit..
But my suggestion..
When no user connected.. Stop your qlikview server service.
and open qv.exe
now you open your first file.. now see the changes in task manager.. (RAM and CPU utilized by QV.exe)
then close the first file and open 2nd file and check once again.. like this you have to study for all files...
like this you can find the ram and CPU usage by each file.. This help you to do optimization..
Or you can use "Governance Dashboard" or use HIC's memory statistic recipie