TestingResults.md

A Comparison of VBA StringBuilder Implementations

The following implementations were tested

Name	Implementation Notes
StringChunker	String base, with in place modification
StringBuffer	String base, with in place modification, managed through a buffer
clsStringBuilder	Byte array base
StringBuilder	String base, with in place modification, managed through a buffer

All times are in miliseconds and represent the average of 30 repetitions.

My Results

The first append test involved appending a single character to the end of the string using the library's append or concatenation function.

Iterations	Default	clsStringBuilder	StringChunker	StringBuffer	StringBuilder
102	0	1	0	0	0
103	2	1	1	0	1
104	170	8	6	2	3
105	N/A	103	58	23	30
106	N/A	747	525	155	320

An additional test was performed to better simulate real word use by appending a word of random letters between 1 and 10 characters.

Iterations	Default	clsStringBuilder	StringChunker	StringBuffer	StringBuilder
102	0	1	1	1	1
103	3	4	3	3	3
104	81	32	25	21	22
105	31259	322	249	216	241
106	N/A	3345	2551	2222	2386

Further Reading

For more information on why the performance of the StringBuilder classes far outperform regular concatenation, refer to the following articles on the Desktop Liberation blog here and here.