We are getting near the end of development of Simple:Press 5.5 and are deep into the testing phase. If all goes to plan, we hope to release 5.5 the weekend of June 1. One of the things we recently completed on 5.5. was another serious round of database query optimization.
With some of the structural changes made in recent versions, ie adding of more caching and reusable objects, it was time again to see how much more db performance we could eek out. Depending on your configuration and plugins in play, you may see as much as a 33% reduction in the number of queries on the main forum page views of group, forum and topic views. That is a significant reduction in query numbers but may not mean a pure 33% performance increase in rendering because not all queries are created equal. But, things should be snappier!
Potentially even more important, we have identified areas for further work (too late in 5.5 cycle for large changes) on caching and db queries. We will hit those during the 5.5.1 development efforts.