How is your data-model - several fact-tables with a link-table or a single fact-table. Both approaches have advantages and disadvantages. Beside reducing unnecessary fields and rows could be a split from high-cardinality fields save RAM. Also section access caused longer load-times.
In the QlikView Design Blog, Miguel wrote a nice article about the impact of reducing unique field values on document size (both on disk and in RAM). These apparently simple changes cause an immediate performance increase. Well worth your time: