For about two weeks now I have found the forum to be very very slow to load. Other websites are not affected. Since the upgrade it is no faster.
I find slowness to be very time-of-day dependant, and for me it tends to hit all parts of the site at the same time. If the forum times out then the gallery and main site tend to time out as well. Usually I find these times of slowness to be short-lived. Generally I blame my net connection. It might be worth logging the time we notice problems, preferably to nearest minute (or five) rather than something vague. That way we can maybe relate it to the logs we get, and try to figure out whether there's a pattern.
The forum database is about ten times bigger than the main site's database, and twenty times bigger than the gallery's one. That might account for some performance difference. Busy times might also make a difference.
(The updates were security ones this time round.)