• That's a vague question. Entire books have been written on the subject.

    Start with these:

    http://www.simple-talk.com/sql/performance/finding-the-causes-of-poor-performance-in-sql-server,-part-1/

    http://www.simple-talk.com/sql/performance/finding-the-causes-of-poor-performance-in-sql-server,-part-2/

    Then consider Grant Fritchey's book:

    http://www.amazon.com/Server-Performance-Tuning-Distilled-Experts/dp/1430219025/

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
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