Try turning off Live Preflight and the page thumbnails in the Pages panel.
Thank you very much for quick response.
I tried after changing these options but not improved . Any other suggestions please.
Are you using nested GREP or Line styles as part of the paragraph styles? Conditional Text? Variables or Hyperlinks/Cross-References?
Off the top of my head I can't think of much else other than under-powered hardware that would cause this type of slowdown.
You could try this: Remove minor corruption by exporting
That is an unpatched version of CC2014. I would update to CC2015 or at the very least run the updates for CC2014.