The prefect count configures how many objects of a query-result are loaded from the server. Prefetched objects avoid additional roundtrip's to the server for getting the data. However more data needs to be sent to the clients.
ClientConfiguration configuration = Db4oClientServer.newClientConfiguration(); configuration.prefetchObjectCount(500);
The prefetch depth and the prefetch object count are closely related to each other. The prefetch object count configures how many objects are prefetched from a query-result. The prefetch-depth configures how deep the object-graph is fetched.