Keeping data in an unordered text file is terrible for performance.
The problem isn't that the data was unordered, hash tables are unordered as well.
Hash tables are associative arrays, that's the important part which explains why it's so fast compared to his text file routine, because the data is already associated with the nickname, there's no need to browse 2000 lines for 2000 entries for nothing, you already know which line it is (basically).
@OP: it's better to keep the hash table; if you need two text files for excel, you should keep that hash table and makes a new function, which will extract the data in two different text file from the hash table, that function can be slow, it's only used manually by you, shouldn't be a problem.
And you still didn't clarify, is mIRC freezing (it shows 'not responding' in the titlebar, eventually windows reports that the program is not responding and ask you to close it but you can always click 'wait' here) or is mIRC crashing (mirc.exe is shutdown and you can't see the mIRC main window, you can't see anything but eventually windows reporting that the application crashed)
Getting a freeze is normal, getting a crash is not, regardless of how bad your script can be, if you see a crash your should report it.
