Ok, things are getting a bit clearer now. Yes, I've been reading the Mediawiki pages on performance tuning. Too bad pretty much all of the options are not available at my current host.
This pretty much sums up hostgator's policy on PHP accelerators:
http://support.hostgator.com/articles/pre-sales-policies/is-it-possible-to-install-ioncube-php-accelerator-on-shared-serverI put all of my jobs queue on a cron a long time ago. I enabled file caching, but that really only helps visitors to the site, not logged in users. I turned on logging, but have yet to see any thing of significance. I guess I could post the log file here. I haven't tried using the mediawiki profiler either.
I seem to get only intermittent delays though. Sometimes the pages load fast, sometimes really slow. Hmmm.