One more thing: Swapping/Paging! The least thing you need to ensure is that you have enough RAM to hold your 10 WorkSheets in memory without paging/swapping involved. Depending on your workbook, that can be huge memory!
As soon as swapping/paging kicks in, any performance measurement is useless because IO will be the bottleneck and dominate your tests. On Unix/Linux, engage VMSTAT and ensure, there is no SO/SI shown during your test. Good luck Andreas
