Seeing long PHP/Apache requests - actual site code takes 1/4 of the request time

[awdev]

I've recently installed Zend Server 5 (PHP 5.3) to take advantage of doing some code traces while improving performance in some areas of my app.

 

I've been looking through some of my code traces where there are long request times.

 

Sometimes I see long REQUEST times with only ~25% of the actual time going into the actual code execution (i.e. from index.php on)

 

I was wondering if anyone was familiar with this sort of thing and would appreciate any help.