It's not "unicode" that's slowing it down. It's the fact that the data is non-UTF16 that's slowing it down, so an option wouldn't be helpful besides for compatibility sake. Even if the data was ASCII, mIRC would still need to convert it to UTF-16 when reading it, since mIRC stores all internal data as UTF-16. This is why I suggested storing the data as UTF-16, so mIRC would not need to perform any conversion.
