Bottleneck with external tests

Please help me diagnose a problem I can't handle. Since two days ago I have a huge perfomance problem. I think it is related to external tests, because when I disable them everything comes to normal. But the amount of spam that enters is unacceptable by our users.
Version of spamassassin is 3.1.3 running on Perl version 5.8.4 (I use it thru Amavis)
Latest version of rules are used, and I have erased rules regarding Razor and Pyzor

Any help will be appreciated. Thanks

Claudia Burman
El Bolsón
Argentina Received on Wed Aug 15 12:46:08 2007