[Exim] Spamd and exim using all the cpu

I am running exim which calls spamd from within exiscan. The spamd
configuration is as follows: spamd -a -d -x -m 10. It is setup to scan
only external mail. Yet at times the machine comes to a stand still,
with load average about 30. The number of spamd running at this moment
is 12. perl -MSocket -e'print SOMAXCONN' gives the number 5. We are
using a SunFire 280R box, with 4GB of memory and 2 cpu.

Is there anything I can do to improve the performance.

Ps. I run the RBL first to cut down most of the spam, and only then
SpamAssassin is run.


Regards

Sujit
-----------------------------------
Sujit Choudhury
ISLS
University of Westminster
115 New Cavendish Street, London
E-Mail: S.Choudhury@???
Tel No: 020 - 7911 5000 Ext 3851