Occasionally m-Fin FINANCIAL DETAIL takes 3 or 4 minutes when it should take only 15 seconds.  Here are some work-arounds you might try:

• Run for fewer periods of data.  Typically the abnormal slowness occurs on requests for all periods in a fiscal year.
• Run for just Budget and Actuals, or even better, just Actuals, instead of Budget, Actuals, and Encumbrances.

Eventually we'll have a second, alternative detail report named m-Fin FINANCIAL DETAIL II and we expect it should run full FY's consistently well.