My app will typically work with 6 workbooks instantiated (one window each) simultaneously.
User will work interactively with the worksheets, just like he would if Excel was used.
After some editing, he/she will perform some heavy access of data (mostly reading), processing the data and send the outputs to another application (as xml documents by COM interface)
As a test I instantiate 6 spreadsheets, one window each and load them with the same xlsx file.
The loaded workbook filesize is about 430 kBytes and contains 37 worksheets (no graphs or other graphics, just plain worksheets) with a total of 45520 cells with data and 1489 formulas (according to Excel/Review/Workbook Statistics) .
My testmachine has an i7-8700 cpu (6 cores) and available memory before application start of about 24 GBytes of rwm.
The opening time until all 6 spreadsheets are visible and editable on screen is about 90 seconds and final working set is about 1.4 GBytes(!!).
Using Excel 2021/x64 and opening the same 6 workbook instances (6 different copies to enable single process) takes about 6 seconds with final working set of 237 MBytes.
The cpu load while editing the workbooks seems to be much more demanding than Excel as well, not really measured, probably acceptable.
Accessing cells data (reading plain cell data) seems to be doable with acceptable performance.
The long loading time and the high memory demand is not acceptable and means that I cannot use WPF radSpreadsheet as is and will need advice to lower these numbers if possible.
Using Excel (accessing with Excel COM automation), but I would very much like to avoid the license cost (and more complex application
Finding another component supplier, similar to Telerik radSpreadsheet, but with possibly better performance (I guess it is not proper to ask in this forum for advice of which supplier could be recommended :)