Couchbase's SDK 3.0+ enhances performance testing for durable writes by offering fine-grained control over durability settings, allowing developers to choose from three levels: Majority, MajorityAndPersistToActive, and PersistToMajority, each with different impacts on performance. The testing of durable writes is influenced by factors such as network speed, disk writing speed, and CPU resources, emphasizing the need for a well-configured hosting environment. In public cloud environments, disk and instance type selections significantly affect performance. The Couchbase performance measurement tool, cbc-pillowfight, helps standardize testing with customizable settings for operations, document size, and durability levels, although its speed can exceed the capabilities of slower hosting infrastructures. Proper test setups are vital for obtaining accurate results, as both the database and the environment contribute to the outcomes.