In-memory, the Future - Getting Started with SQL Server 2012 Cube Development - page 311

the images over the employees and the sales territories. If these pictures will not be
used in reports, they should be removed.
If you examine the files that are among the largest non-XML files, you will find that
most of them are on columns that mostly will not be used in queries at all. These
columns can be removed from the model.
Note
For an in-depth description of how the storage in tabular models works including
what the different files contain, see the webcast at http://media.ch9.ms/ch9/19c6/
30cc1b48-0d89-43cb-b20c-7ba64a4019c6/DBI414_mid.mp4 .
To remove columns from the model, you can either remove them from the query
used when importing them, or you can select any column and click on the Delete
button.
Tip
More information about how you can tune tabular models can be found in the
whitepaper at http://msdn.microsoft.com/en-us/library/dn393915.aspx .