There are a few bottlenecks that could be causing this slowdown (this post assumes your server is running Linux). Here are just a sample of the big ones that we've encountered:
- Network congestion: if Jez H's suggestion of using admin/server/debugging shows that your pages are processing quickly, yet displaying slowly in your browser, this indicates some sort of network delay between your machine and the server.
- CPU contention: run 'top' on your server to get an idea of cpu usage while trying to load pages. If CPU usage is high, check out which process is using the most %CPU (could be httpd, mysqld, etc...). This will indicate which process is consuming CPU, taking you one step closer to resolving the issue.
- High load: if your CPU usage is low, yet your "load average" in top is high (over 1.50), then this indicates your server might be I/O constrained from some device (hard drive, networked file system, etc...).
- Non-optimal configuration: I would check how your hosting provider configured MySQL, Apache, and PHP (my.cnf, httpd.conf, and php.ini respectively). If you continue to experience delays and the posted suggestions do not identify the source of the delay, you may want to post these three configuration files for other moodlers to analyze & comment on.
"Also I don't understand "you don't run SCORM content on moodle instance" is there another way?"
What I meant by my comment is that in my moodle instance, I do not have SCORM content and am not familiar with SCORM.
I hope this information is helpful!