Hi Frank,   I have run into the same issue of user defined formats (particularly those with very high cardinality) slowing down report performance whenever data items with UDFs are being used on the report. I have found a workaround for character data (that I mostly use UDFs for) where I create an additional data item with "[raw]"-modifier to force VA to use unformatted values (i.e. define a new data item with something like the following formula: 'Data Item with UDF'n[Raw]) and then use this new data item everywhere instead of the original. This speeds up the report significantly and for some reason all the values are still shown as formatted according to the specified UDF.     I am using VA 7.1 in a non-distributed environment. ... View more