spamassassin slow to process messages

[Andrew Thomson]

I'm looking for some suggestions as to why my spamassassin is so slow!

Installed from ports.

Details:

p5-Mail-SpamAssassin-2.55
5.0-RELEASE-p7

I'm running spamd and using spamc/procmail to pass the messages to
spamd.

I was reading the following,

http://spamassassin.rediris.es/dist/spamd/README.spamd

and it was talking with figures like:

"Well, on my 400MHz K6-2 mail server, spamassassin process a 11689 byte
message in about 3.36 seconds, spamc/spamd processes the same message in
about 0.86 seconds, or about 4 times faster."

I've got a CPU: Pentium III/Pentium III Xeon/Celeron (930.32-MHz
686-class CPU) and I'm seeing performance like,

Jul  8 08:25:11 athomson spamd[52016]: clean message (0.4/5.0) for
ajt:1001 in 10.2 seconds, 2132 bytes. 
Jul  8 08:25:27 athomson spamd[52031]: clean message (0.4/5.0) for
ajt:1001 in 10.2 seconds, 2092 bytes. 
Jul  8 08:30:12 athomson spamd[52074]: identified spam (16.0/5.0) for
ajt:1001 in 10.3 seconds, 3158 bytes. 
Jul  8 08:30:28 athomson spamd[52093]: clean message (-2.1/5.0) for
ajt:1001 in 10.2 seconds, 2847 bytes. 
Jul  8 08:30:44 athomson spamd[52100]: clean message (0.4/5.0) for
ajt:1001 in 10.2 seconds, 2133 bytes. 

Much smaller messages, taking much longer to process!!

ajt.