We found slow queries in the includable adps. Once we resolved the issues that we slowing down the queries the performance increase of those includes was about 10x faster. The home page loads in around 300ms now, which is a huge improvement.
In the case of the ETP includes there was a plpgsql function in the where clause of the get_content_items procedure. I rewrote the query and the performance went from 900ms to around 17ms.
In the case of the forums include there was a view in a subquery that was causing the PG optimize to make a poor choice. When I rewrote the query to use the table directly the increase also was signifigant.
This shows that developer support and explain analyze are very important tools to track down this type of performance issue.
