imp causes high load ?

[serene@home.martnet.com]

Hello,

For some time we have been experiencing very high loads that seems to be
caused by imp.  We are running imap and a small website and basically
nothing much else.  We had tried to upgrade the apache webserver,
but it didn't help that much.
Has anyone ever had a similar experience and are there
any solutions if in fact the high load is due to imp? 


here are what we have:

solaris 2.6
apache 1.3.17 + mod_ssl-2.8.1 + php-4.0.4pl1 + openssl-0.9.6
imp 2.2 and horde 1.2


Thank you very much for any suggestion

se