I am trying to upgrade our SQL Server version from SQL Server 2008 to SQL Server 2008 R2. But when I restored a SQL Server 2008 backup file in SQL Server 2008 R2, it's significantly degraded the performance of stored procedures. I took a full back up from old SQL Server 2008 and restored it in new SQL Server 2008 R2. I checked the execution plan of several stored procedures to make sure no indexes are missing, but everything is same.
Can anyone please give me an advice about it if I need to do any further steps to get better performance on it?