Flash Player 7 String Parsing Performance

I just came across the following in my notes from last year, thought it was worth saving:

When performing String parse operations, the presence of characters above the ASCII 128 character range can slow the parsing significantly. In my case, I was applying String.toLowerCase on a 45000 character string, and it was taking 2.5 seconds. Removing the characters above character code 128 reduced the execution time to just 2 milliseconds.

I have no idea if this applies to Flash Player 8 or 9, but I have a feeling I'll be checking into it soon.