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I am attempting to update the values of all formulas in a large workbook, and have notice a significant loss of calculation performance in XLSIO versions after 16.2400.0.41 ( This is still present in version 17.1460.0.44 (

The issue is especially prevalent when updating formulas that contain large formulas referencing many cells, such as the AVERAGEIFS() formula.

Attached are two sample solutions that demonstrate the issue, with one using version 16.2 of the Syncfusion libraries and the other using version 17.1. Everything else in the solutions is identical, and operates as follows:

1. The program opens the sample Excel workbook

2. A select range of cells containing large formulas are updated. The execution time is displayed on the console after each cell is updated.

3. Upon completion, the total execution time is displayed on the console window.

Using the older version of the libraries, the execution time is in the range of 2-3 minutes, whereas using the latest version it takes over 1 hour. The sample workbook is a very close representation of my real use case, so the significant performance degradation is present in my full application too.

A possible hypothesis I have as to why the new version is performing much worse is that previously-calculated cells are not being correctly marked as such, so subsequent references to them are resulting in their re-calculation. This is simply a guess though so the actual cause may be something else entirely.

My application is run frequently and on large datasets, so I require it to be as performant as possible.

Thanks in advance for the assistance.