Multidimensional OLAP (MOLAP) is faster than Relational OLAP (ROLAP).
MOLAP: Here, data is stored in a multidimensional cube. The storage is not in the relational database but in proprietary formats (one example is PowerOLAP’s .olp file). MOLAP products are compatible with Excel, which can make data interactions easy to learn.
ROLAP: ROLAP products access a relational database by using SQL (structured query language), which is the standard language that is used to define and manipulate data in an RDBMS. Subsequent processing may occur in the RDBMS or within a mid-tier server, which accepts requests from clients, translates them into SQL statements, and passes them on to the RDBMS.