I had a web site on a windows server that was working fine before re-tooling with PHP. Now every time a Credit Card is processed the customers get an hourglass. After a few are processed, IIS needs restarting. Should I move PHP off the windows server onto a UNIX server? I really don't care what platform it runs on. I'm not really looking for Microsoft/PHP evangelists to start preaching a sermon. I just want the best technical information available with quantifiable reasons to back up opinions.