[imp] High load for httpd seen when running imp4/horde3

[imp-archive@cloud9.net]

I'm seeing a problem with our imp4/horde3 setup that was not previously a 
problem with our previous imp3/horde setup.  The load on the machine that 
we are using for the imp/horde system is regularly hitting almost 20 on 
the 5-min average, and with this users are experiencing extreme slowness, 
even some IE users are reporting their browser hanging on redirect.php 
without proceeding to their INBOX page.  I have already installed Turck 
MMCache for PHP, which has sped up the generation of e-mail index lists, 
but this intermittent load issue continues to be a problem.  Whenever I 
look at top, I usually see httpd occupying the top five or six places.

Any advice on where I should look next?

This is the list of parameters my PHP 4.3.11 is compiled with:
'./configure' \
'--with-gettext' \
'--with-xml' \
'--with-mysql' \
'--with-mcrypt' \
'--with-imap' \
'--with-imap-ssl' \
'--with-apxs=/usr/local/apache/bin/apxs' \
'--with-dom' \
'--with-zlib-dir=/usr/local' \
'--with-iconv' \
'--with-mime-magic' \

--
  Mark P. Hennessy
  mark at cloud9.net