An Excel file that we use is only about 2MB in size, but as soon as it is
opened, the memory usage of EXCEL.EXE jumps to over 1GB. We are running
Excel 2007 and this file is saved in the .xlsx format. Weird enough as using
that much memory is, when I save-as that file into Excel 2003 format, close
down Excel and open the new .xls file, EXCEL.EXE memory usage is only about
100MB. Why would a file saved in .xlsx format use 10 times more memory as a
file saved in .xls format? Both files are being opened through Excel 2007.