Is it possible to do a case insensitive comparison of individual characters?
I tried:

Char.ToLowerInvariant(charA).CompareTo(Char.ToLowerInvariant(charB))

And though it works for the most part, it didn't seem to work for all
locales.

I tried converting the characters to a string and then do a case insensitive
comparison, and this always worked.  Unfortunately this comparison is being
called millions of times and converting to a string is terribly inefficient.
Do I have any other options?

Thanks