The screenshot below shows the dependency graph for four separate visualizations, each hooked up to a different column of the table on the right. Note that each visualization takes about two seconds to compute.
When small multiples are used instead of four small visualizations, the four visualizations are replaced with a single visualization. It takes a bit longer to compute, but, in most situations will be faster (the separate visualizations will be faster if nothing else is being done on the server at the same time, as the calculations will be done in parallel).
To better understand why this visualization works, see Reduce the Number of Calculations in a Document.