Created attachment 140357 [details]
Example file with lots of random data

LibreOffice Calc has very high memory consumption when dealing with lots of data on multiple worksheets compared to Microsoft Excel. The result is that Calc is unable to open more complex spreadsheets that work just fine in Microsoft Excel on the same computer.

Steps to reproduce:
1. Create a new spreadsheet in LibreOffice Calc.
2. Add a simple function (e.g. =RAND()*1000000) to many (tens of thousands) of cells on the first worksheet.
3. Copy the content of the first Sheet to multiple Sheets.
4. Sum the values from multiple sheets on the last sheet.
4. Save the file as XLSX.
5. Open the file in LibreOffice Calc and in Microsoft Excel.
6. Compare the memory consumption of the two applications.

Actual results:
The memory consumption of LibreOffice Calc is many times higher than the memory consumption of Microsoft Excel. The memory consumption of Calc is even higher when opening the XLSX file.

Expected results:
The memory consumption of LibreOffice Calc should be lower when dealing with lots of data.