Well, Aspose.Cells is a pure .NET component created in managed C#, so , concurrency and multithreading is not a problem by any means. For your information, as long as you don’t have shared data source and every time a user access a new Workbook or Excel file in different thread, there would be no problem at all. However, if you have a shared data/resource or the same Excel file/ workbook, then you will have to do synchronization by yourself. Also, in that case, we recommend you to create/manipulate of filling data into different workbooks and calculate formulas for different spreadsheets in different threads accordingly, because, you should not use one workbook/file in multiple threads at the same time least you would not get stable data (there is global shared data/ resources in Excel file spreadsheets, so knowing the nature of the Excel file formats, you should not share a workbook in multiple threads), I am afraid.
By the way, to enhance the performance, you may use memory optimization options for your needs:
Thanks for your understanding!