The most important performance-tuning technique available is having the needed indexes created on the tables to ensure that the SQL Server database engine is able to get the data that it needs to ...

I always recommended disabling first so that if you need the index back you can quickly rebuild the index (making it available again without needing to go and find the SQL Code to create the inde)x.

SQL Server 2012 includes a lot of new and exciting features. One feature that has caught the imagination of many in the user community is the high-performance feature called Columnstore Indexes.