*low whistle* What network are you on? On the most picky network I'm on, a 1600-user channel does a single /who #chan happily.
That being said, I had to stagger IAL updates for when first joining channels on the network as it used to sendQ. It wasn't the single /who that killed it, it was 12 at the same time (even though none of those individual channels were larger than 300 members).
If you just /who each individual member of the channel, you're more than likely going to trigger a ReceiveQ flood.
Can you give us the network/server name, and an example channel name with large members so we can test?
