page execution time

Hi -

My drupal install is experiencing very high page execution times and the CPU spikes to 100% when I first load a page. Upon reloading that same page, things happen faster, but the execution times still are high and CPU often gets up to 60-70%. This is for authenticated users. For anonymous users, the site is performing well.

Server stats/info

php running as mod_php

Average daily page views is very modest - 400, peak 700

Running eAccelerator with 128MB
Running Boost 6.x-1.18

While investigating a large descrepancy between query time ( 243 queries taking roughly 37 milliseconds) and total page execution time ~390 millisecond, I looked at various filters I have installed. I noticed video filter module added a significant overhead and by disabling it was abale to reduce the page execution time to ~212 milliseconds. I also opened an issue for the module here http://drupal.org/node/375415 and you can see more details about my test.

I already use APC.

Are there other filters or modules that you aware could add significant overhead to page execution time?