Did you read about Hyper ?
Faster analytics with Hyper
Hyper is Tableau’s new in-memory data engine technology, designed for fast data ingest and analytical query processing on large or complex data sets. Included with Tableau 10.5, Hyper can slice and dice massive volumes of data in seconds, you will see up to 5X faster query speed and up to 3X faster extract creation speed. With enhanced extract and query performance, and support for even larger datasets, you can choose to extract your data based on the needs of your business.