It’s suggested you use SQL Profiler trace data ove layed against system information found in the performance monitor. However, to get a quick look at what queries may be slowing down performance , run the following –
select ss.sum_execution_count , t.text , ss.sum_total_elapsed_time ,ss.sum_total_worker_time , ss.sum_total_logical_reads , ss.sum_total_logical_writes from (Select s.plan_handle , sum(s.execution_count) sum_execution_count , sum(s.total_elapsed_time) sum_total_elapsed_time , sum(s.total_worker_time) sum_total_worker_time , sum(s.total_logical_reads) sum_total_logical_reads , sum(s.total_logical_writes) sum_total_logical_writes from sys.dm_exec_query_stats s group by s.plan_handle ) as ss cross apply sys.dm_exec_sql_text(ss.plan_handle) t order by sum_total_logical_reads DESC