>I am a beginner in VB6, please inform me which is the fastest DAO, ADO or RDO? any answer is highly appreciated and thank you very much

It is heavily related to your database engine.

You should consider using the technology that is the most current (ADO) since DAO slightly evolved since ADO is out and RDO is almost dead (no new version since VB5).

You should consider the latest version of ADO (2.5).