Before someone marks this question as duplicate : I have tried the common fix for this problem by installing the 295.33 series driver as suggested elsewhere.
I have also removed my compiz-1 settings and .compiz-1 and .compiz and started afresh.
Despite all this Unity 3d works snappily only in the guest-session.
In my regular session, the performance is terribly slow. Window dont erase..moving the terminal around gets hundreds of ghosted windows. The Guest-session on the same machine has seemingly flawless Unity performance ( it was so good I check by echo $DESKTOP_SESSION and it was indeed Unity 3d).
What in my setup is causing slow laggy performance as the non-guest user? Just deleting the .config/compiz and .config/compiz-1 and ~/.compiz and ~/.compiz-1 settings doesnt seem to sort out my compiz settings and give me guest session like performance.