how do I Performance tune apache for rc?

[syadnom]

Can anyone offer any advice on performance tuning apache specifically for RC?  I am running a Centos5.2 mailserver with dovecot/postfix and roundcube for webmail.  Apache uses 40% of the server's memory.

Now, I know that just adding memory is a good way to solve this but I want to know how to tune apache to deliver the best RC experience and reduce memory.

Thanks