I want to add more detail to the problem:
I have vtk-5.4 on core i3 machine.
I have used PCL cloudviewer example(link given in earlier post) on other machine with vtk-5.8 and it was working without any 'freezing' problem.(although that machine is core i5)
So can it be a problem due to outdated vtk library used?
Please tell if more details are required(like code profiler output,process viewer snapshot etc).