After migrating one of the 2010 sites to sharepoint 2013 it's loading the default page in 16 s or more; although in 2010 it takes 4 seconds only

Hi,

After migrating one of the 2010 sites to sharepoint 2013 it's loading the default page in 16 s or more; although in 2010 it takes 4 seconds only.Few of this pages contains custom webparts which populate datafrom list based on the login user to show few of the fields .Which use to work with out any performance issue in sharepoint 2010.But now we are getting connection time out as well some times..

• EnsureListItemsData (549.93 ms)
  • SPSqlClient (21.36 ms)
  • SPSqlClient (523.56 ms)
• SPSqlClient (527.64 ms)
• EnsureListItemsData (533.63 ms)
  • SPSqlClient (529.16 ms)
• SPSqlClient (520.31 ms)
• SPSqlClient (18.44 ms)
• SPSqlClient (527.41 ms)
• SPSqlClient (515.56 ms)
• SPSqlClient (17.09 ms)

Thanks & Regards, Krishna