The standard seems to be (at least on most ircd) that you can send 5 lines at once before it enters them into some sort of a queue. If you send 5 lines separated by $crlf all at one time, it will do all 5 commands immediately, then slowly finish the rest one by one. This limits you to 30 modes before it bogs down.
Some daemons might be different, but the last time I did any extensive testing on undernet, efnet, etc, this was the case.
