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Getting Consistent Results from FastExcel V4 Timing
Sometimes you will find that your FastExcel timing results are not repeatable, even though FastExcel measures elapsed time using a high-resolution timer with microsecond accuracy.
Power Saving and Multi- Core processors:
Power saving features, particularly on dual-core processors, may dynamically vary the speed of your processor. This can create problems for consistent timings using the high-resolution timer. If timing consistency is important try switching off the power-saving features of your processor.
Excel minimizes the number of calculations:
When Excel calculates it remembers:
Which cells have been calculated.
The optimum calculation path used for the final answer.
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The second calculate is often much faster than the first
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So the next time Excel calculates it can save time by:
Only calculating the cells that have changed (or depend on cells that have changed)
Re-using the last calculation path
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Why FastExcel Timing results may vary from run to run:
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Both Excel and Windows cache information to speed up subsequent operations
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Both Excel and Windows try to optimize performance by storing recent information in memory. This includes the calculation path used by the most recent calculation.
So Excel’s second calculate is often significantly faster than the first.
Excel also saves some of this information, including the most recent calculation path, with the workbook.
Windows is a multitasking, paged virtual memory operating system so other system tasks are always running at the same time as Excel. Try and make sure there are no other user tasks active whilst you are using FastExcel.
Excel’s background calculation process can be interrupted if you press any key or click the mouse whilst FastExcel is active. This may give you inaccurate timings.
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Windows is a multitasking system so Excel does not get the whole system to itself
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Excel’s background calculation process can easily be interrupted
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FastExcel V4 can help you quickly find out how much memory Excel is using.
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