Parallel plans mean that cpu_time can be greater than total_elapsed time. Therefore, per-query wait time is not possible to determine accurately from DMVs on servers with more than one CPU thread. ...
Why does removing a RID by creating a clustered index lose parallelism and slow down execution by 2X
If I remove a RID lookup by replacing 2 non-clustered indices (non unique) with 2 identical clustered indicies (non-unique) where there weren't any before, why does this query slow down by a factor ...