A couple of weeks ago I asked for help because of the inability to access Add Content Type and about the php memory error where drupal requests more memory than php or a server can allow. I received several helpful responses but no answer.
It was suggested that "something" was loading up memory, this was absolutely correct. The fault is Token and Pathauto modules lazy loading everything in the system, most of which is completely unnecessary for the required process, thus overloading memory. The system simply grinds to a halt.
If I shut down Pathauto and Token the system runs at lightening speed. Maybe someone with php skills can rewrite Token and Pathauto Cheers Roger