This research paper examines the architectural designs and performance tradeoffs of various Cloud Database Management Systems (DBMS). The authors evaluate popular platforms such as Redshift, Vertica, Presto, and Athena using a standardized business analytics workload. A primary focus is the shift from traditional shared-nothing architectures to cloud-native shared-disk models that separate compute power from remote storage. The study analyzes critical factors including initialization times, scalability, and data compatibility across different cloud storage formats. Furthermore, it provides a detailed cost-benefit analysis comparing self-managed instances against serverless DBMS-as-a-service offerings. Ultimately, the findings help organizations choose the right configuration by highlighting how caching, storage types, and licensing impact overall efficiency.