Isolated storage best way to store data in Windows phone -

i storing data windows phone isolated storage using below code performance slow because chat application need store message continuously.what best way achieve .sometimes throw memory issue.

my code storing data

 using (mydatacontext objdb = new mydatacontext(dbconnectionstring))                      {                          mytable newrecord = new mytable       {        message = "newmsg",        from="abc",       date="22/2/33"      };       objdb.mytabledetails.insertonsubmit(newrecord);       bjdb.submitchanges();    } }