A common mistake made by many web developer is to develop a site on a local machine with direct access to the data, or to develop the site over a high-speed Internet connection. Sometimes developers are not aware of the fact that some of their pages take a long time to download.
Internet usability studies tell us that most visitors will leave a Web page that takes more than 7 seconds to download.
Before you publish any content heavy pages, make sure they are tested over a low-speed modem connection. If your pages take a long time to download, you might consider removing some of your graphic or multimedia content.