A model created to define the significant aspects of the way in which a proposed or actual system operates in terms of resources consumed, contention for resources, and delays introduced by processing or physical limitations (such as speed, bandwidth of communications, access latency, etc.). The creation of a model can provide insight into how a proposed or actual system will or does work.

A model will often be created specifically so that it can be interpreted by a software tool that simulates the system’s behaviour, based on the information contained in the performance model. Such tools provide further insight into the system’s behaviour, and can be used to identify bottlenecks or hot spots where the design is inadequate. Solutions to the problems identified might involve provision of more physical resources, or change in the structure of the design.