Hallo Prasad,
no, I am not aware of such a change.
Maybe you should look at individual runtimes of selected transactions/reports rather than the overall picture?
As I mentioned those times are usually averages over the period of the uptime of the server. The same applies to the database. E.g. if you run Oracle and your buffers haven't really loaded everything has to be read from disk rather than being already in memory.
Regards
Thomas.