How to improve spreadsheet speed when single-threaded VBA is the bottleneck.

Question

My brother works with massive Excel spreadsheets and needs to speed them up. Gigabytes in size and often with a million rows and many sheets within the workbook. He's already refined the sheets to take advantage of Excel's multi-thread recalculation and
seen significant improvements, but he's hit a stumbling block. He uses extensive VBA code to aid clarity, but the VB engine is single-threaded, and these relatively simple functions can be called millions of times. Some functions are trivial (e.g. conversion
functions) and just for clarity and easily unwound (at the expense of clarity), some could be unwound but that would make the spreadsheets much more complex, and others could not be unwound. 
He's aware of http://www.analystcave.com/excel-vba-multithreading-tool/ and similar tools but they don't help as the granularity is insufficiently fine. 
So what can he do? A search shows requests for multi-threaded VBA going back over a decade.
qts

Answer 1

Hi,
>> The VB engine is single-threaded, and these relatively simple functions can be called millions of times.
The Office Object Model is
Single-Threaded Apartments, if the performance bottleneck is the Excel Object Model operation, the multiple-thread will not improve the performance significantly.
>> How to improve spreadsheet speed when single-threaded VBA is the bottleneck.
The performance optimization should be based on the business. Since I’m not familiar with your business, so I can only give you some general suggestions from the technical perspective. According to your description, the size of the spreadsheet had reached
Gigabytes and data volume is about 1 million rows. If so, I will suggest you storing the data to SQL Server and then use the analysis tools (e.g. Power Pivot).
Create a memory-efficient Data Model using Excel 2013
and the Power Pivot add-in
As
ryguy72 suggested, you can also leverage some other third party data processing tool
according to your business requirement.
Regards,
Jeffrey
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