Taking PHP + MySQL to the max

I am working on a forum using PHP + MySQL which looks strikingly similar to UBB based boards, but with all the tweaks, hacks, etc. :) The problem I encountered is that when I compared just by view thread on the PHP based forum and the UBB based board (both on the same server), the PHP script was a tad slower to show the thread. I am using about 3-5 queries for perhaps most of the functions performed. Is that slowing the board down? I have a few tables to keep it organized, but yet, I think that querying 3-4 tables to perform one function slows down the script incredibly. So my question is, what ways could I actually speed up the script? I've talked to one PHP guy and he told me instead of putting the data into seperate columns in the table, put all the info into one column, seperating the data with delimeters which PHP will parse and retrieve the info. How would that help if I am having 8 columns, and sometimes I just want to pull one column of information? Thanks for any help with this. . . BTW, I am using PHP3 with out Zend, so maybe PHP4 would be faster? ;)