Depending on the application-specific functionality, a distinction is made between thin clients, fat clients and rich clients. In contrast to thin clients, fat clients are fully equipped, powerful desktops with high- performance processors and sufficiently high computing power, hard disk storage or solid-state drives, various drives, high-performance graphics cards and a network connection.
A fat client or thick client has its own operating system and various application programs. It has all the presentation and application logic functions implemented. As standalone computers, fat clients can be operated in a client- server architecture with several clients. They can serve as servers and are not dependent on other servers.
The performance of fat clients has the advantage for users that they can access a high level of offline functionality and convenience, which makes them largely independent of networks. Fat clients have the entire application installed on them and are processed by them. The data is retrieved from the server, to which the fat client has an open interface.
On the other hand, there is a higher effort for the updating of updates and new application programs. The fat client is clearly differentiated from the thin client, but there are some overlaps with the rich client. For example, both clients are usually independent of a platform, the fat client has a higher update functionality and is not based on a component model like the rich client.
The decisive factor for the use of a fat client is that it works autonomously and can process many standard programs offline. If the network bandwidth is sufficiently large, then the clients can be used for more complex programs. And due to its high computing power, fat clients can process several tasks simultaneously.