Thank you everyone for your replies...
So let's ask about your environment. How many people are you serving? If there are "many", are they a relatively homogeneous group? Are you contemplating using your own smtp server? (Modern spam filtering has made this a nice experience on receipt of email and a little more difficult for administering the send side of the world. These days you must be careful about your rDNS and SPF setups for best anti- spam performance.)
I'm running a mid powered P4 box with 512MB ram running as a web server (only 10 small web sites) with about 20 mailboxes at present so we're talking a low amount of users... In another reply you mentioned about your 1GHz using just shy of 3 secs processing time for each mail so I guess with a lower spec box I will have to be careful about using resources. The server has been set up by my ISP and now I am driving it :) So at the moment it's an exercise it finding out what's installed and how's it's working! It's handling mail and I know SendMail is how it's happening - So to answer your question about whether I am using my own smtp server - I think so - how can I tell? I have installed FC5 on a box at home so I can experiment and make my mistakes in a private arena! I'll search for you previous posts... Thanks again everyone... Chris