What is the fundamental difference between a fat-client and a thin-client approach to client-server system architectures?

The fundamental difference between fat-client and thin-client architectures lies in where processing power and application functionalities reside. A fat client, or thick client, performs most processing and application functions locally on the user's device, requiring less reliance on the server for processing tasks. In contrast, a thin client relies heavily on the server for processing, with minimal application logic and data stored locally, which allows for easier maintenance and lower hardware requirements. This distinction impacts performance, scalability, and user experience depending on network conditions and server capabilities.