The forum seems to be slowing down in this manner:
The initial connection is slow (when I first come to the site and click "Forum" on the top menu bar).
It is then fast as long as I interact with it. If, however, I take the time to compose a substantive post or do something else for a while, it is again slow at the first new click. Previewing a post used to be instantaneous, but now it takes several seconds to load.
A guess as to the cause would be not having sufficient idle database connections in the pool so that one has to become available again before a request can be handled. And then the connection being handed off to someone else if the interaction is not kept up. Just a possibility.
In any event, I'm mentioning in case others are experiencing it because it might mean the forum database needs some kind of tweak or performance will continue to degrade.