We had been running 2.3 since December on a new server we setup just for Moodle 2, and while the performance wasn't as good as our 1.9 servers, it was tolerable. Admin user pages were loading in 3-5 seconds, and non-Admin user pages were loading in <2 seconds. Once we upgraded to 2.4.3+, the response time was terrible, >30 seconds for admin and about 15 seconds a page for non-admins, completely the opposite affect I thought upgraded to 2.4 would have with the new caching in this version.
Through a number of changes I've been able to cut this in about half for admins and less than 1/3 for non-admins, as admin user pages are now taking 13-16 seconds to load, and non-admins 1.5-3.5 seconds depending on the page. The major changes were moving the Moodle Data from a UNC share to a local drive, and changing the SQL server driver from freeTDS to the native MS driver. But the performance is still dissapointing, especially for admin users, and still slower than 2.3. Any ideas on why the performance got worse would be appreciated.
I do have xDebug installed and can profile some pages if that would help, when I've looked at them no single thing stands out to me. Just lots of functions that are taking >1 second that I'm guessing should not.