Software updates slowing you down? We've all shared the frustration -- software updates that are intended to make our applications run faster inadvertently end up doing just the opposite. These bugs, dubbed in the computer science field as performance regressions, are time-consuming to fix since locating software errors normally requires substantial human intervention. Source 9e.
I always find its 50/50 sometimes an update will speed things up and other times it will just slow things down a lot.