After performing the system change, create a post-change SQL trial. It is highly recommended that you create the post-change SQL trial using the same method as the pre-change SQL trial. Once built, the post-change SQL trial represents a new set of performance data that can be used to compare to the pre-change version. The results are stored in a new, or post-change, SQL trial.
Creating a Post-Change SQL Trial for information about how to measure the post-change performance