system.opc.browse is terribly inefficient - it does a deep, recursive browse, using the path to filter out results, but it still browses everything.
system.opc.browseServer, while harder to use because you must handle recursively browsing yourself, can be more efficient because you can control which folders get descended into during the browse.
This post contains a simple example of using the function: inductiveautomation.com/forum/v … ver#p50741