The bottom line is that if that connection overhead is high, persistent connections help you considerably.
Actuellement, PHP 4 supporte ISAPI, WSAPI, et NSAPI (sous Windows), qui permettent tous d'utiliser PHP comme un module sur un serveur multi-threads tel que Netscape FastTrack (iPlanet), Microsoft's Internet Information Server (IIS), et O'Reilly 's WebSite Pro.