Check the profiler in several frontend/backend pages and notice the more ACL checks are done the more is the performance improvements.
Check if ACL permissions work fine (do multiple tests). Make sure there are no ACL breachs after this.
The performance improvements are particular higher when logged in with a non-root user and a lot of modules (since in this cases there are a lot of ACL checks).
Just an additional info.
This is the performance/memory usage difference with a logged (non super user) joomla clean test sample data install frontend home page.
Just an additional info.
This is the performance/memory usage difference with a logged (non super user) joomla clean test sample data install frontend home page.
Before
After