Also take care in your model constructors with loading the database. I have found I use the database so much, for sessions and such, that it makes more sense to just autoload the database. Then you don’t have to worry about making calls to load it.
For extra memory security in such instances, you might try something like this:
if (! is_set($CI->myModel))
{
$CI->load->model( 'myModel' );
}This way you guarantee you aren’t loading something twice, leaving no chance things are being loaded more times than you want.
And as you code notes, in models be sure to make use of the CI super-object on loading so each model doesn’t itself end up with its own sub-model and you end up with dozens of duplicates flying around.
Glad you got to the bottom of your problem!