I dunno of a way to slow it down, I don't
think you can...
/list includes all those channels with 2/3 users, perhaps it might help to use the
/list > N command to cut off the tiny channels you might not necessarily want?
Usually there's not a huge reason to get a complete list of channels on the top networks, it takes ages and it's impossible to look through each one...
Hope someone comes up with an answer though
Regards,