Ok, I've written code that parses a file and replaces one text/byte(s) code with another. Now in VB6, you can read a 2MB file into a string, in memory, and doing a simple replace all at once and then writing over the old file was much faster than the traditional line by line method of drilling through the file, while writing to another followed by the delete of the old one and rename of the new to match the old.
It came in handy when converting large .CSV files with lines terminated with CR to CR/LF and vice versa.
File access is slow compared to memory access, hence having the entire file in memory was ideal and VB's "Replace" command allows you to use any sequence of bytes. It's not just limited to 7 bit ascii.
This turned a batch processing job of many large files into one that went from taking over an hour to taking just several minutes.