I would start by reviewing the Onine Help on performnace. It contains a myriad of tips and tricks to address slow performance in a work book.
Additionally there are several white papers and blogs that address the performance of a Tableau workbook.
Also if you could share some additional details on what is occurring in the workbook and the performance recording the community might be able to assist in more targeted fashion. What is taking the longest in the performance recording? Workbook opening, viz rendering, connecting to the data? Additionally, what data source is be used? Is the data source live or extracted?
Hope this helps!