The extraordinary growth in the World Wide Web has been sweeping through business and industry. By using web technologies many companies have developed or integrated their critical applications. Testing web applications become crucial, particularly as performance of web applications become complex. Performance of many Web sites depends on the load on the site at peak time under varying conditions. Performance testing is normally conducted with the help of performance testing tools in a reasonable simulated environment. As user is the ultimate judge for the success of web site. Performance perceived by the user is most crucial. Due to complexity of web site, it is not possible to draw a common denominator for user perception of the Web site and designer's viewpoint. It is necessary to analyze the users perceptions and modulate to fit into the designer's shoes in such circumstance. This paper proposes a new model, which enforces the designer to incorporate the users perception by projecting and modulating the perceptions. Later, the designer would consider the projected perceptions during the performance testing without diluting the reliability.