very slow response times

[Dana Holland]

At times our server takes quite a while to process incoming email - it's 
not at all unusual for an email to take a couple of hours or more to get 
through the system from the time it hits the server.  Local email may 
take as much as 5 minutes.  I'm just wondering if an increase in RAM on 
the server might help with this.  There's definitely been a slowdown 
since we installed spamassassin.

Our server is running RedHat Linux 8.09, with 2gb of RAM - we're running 
sendmail 8.13.