The Nginx experiment is over. It didn’t reduce the load on my server, it did quite the opposite in fact which might have been a result of using php5-cgi. The load went up after I changed to Nginx, and when I installed P2 it made things worse because of the p2ajax requests looking for updates. Supercache can’t cache those requests so PHP was being executed for each of those requests, and there were a lot of them. People leave their browsers open all day!