The decision cube's MaxDimensions and MaxSummaries properties can be used with the CubeDim.ActiveFlag property to control how many dimensions and summaries can be loaded at a time. You can set the maximum values on the Cube Capacity page of the Decision Cube editor to place some overall control on how many dimensions or summaries can be brought into memory at the same time. 

Limiting the number of dimensions or summaries provides a rough limit on the amount of memory used by the decision cube. However, it does not distinguish between dimensions with many values and those with only a few. For greater control of the absolute memory demands of the decision cube, you can also limit the number of cells in the cube. Set the maximum number of cells on the Cube Capacity page of the Decision Cube editor.