ya thats my bad by freeze i ment lag since mIRC is single threaded and the socket loop for a server gets high priority (as it should) as i said there is little that can be done on big networks even code wise, the only stuff i can think of would slow the filling of the list down overall but would keep it from lagging... though i think its best the way it is.l
Also I ment stop immediatly since even once you send list stop or halt or what not the server still sends a bunch before stopping, though like i said i do not think there is a command in the irc protocol that is standard to stop /list though as you said some networks implement a way
