Abstract: Performance modeling and simulation offer powerful approaches to predict performance characteristics of software applications and in particular web applications. At the same time the usage of modeling techniques in real projects is still limited due to comprehensive structure of applications and impossibility to know internal structure of applications components needed to create a precise model. In our work we build and evaluate the high level abstraction models of Content Management System Joomla to estimate their ability to provide reliable predictions for different performance characteristics. To build the models we consider three formalisms: Layered Queuing Networks, Performance Evaluation Process Algebra and Queuing Petri Nets. Predictions obtained from models simulation have been compared with measurements of the real system by HP Load Runner toolkit. Results show that overall throughput of the system can be predicted with high level of accuracy while prediction of response time by the same models is less reliable.