I connect thru a winproxy firewall at work. I am the admin of the firewall and the net admin and general all around computer guy at work.
I chat on one network irc.freenode.com in which every time I connect it takes like 5 minute before I can join a room. I will type /j blenderchat or /j windows and the server box will just sit three several minutes the the channel box will pop up. When I type in a channel I can see my typing but, its as though no on else is talking. Then 5-10 minutes later 30 lines will scroll by.
These thing happen OCCASIONALLY on other irc networks but ALWAYS on freenode.
The thing about it is that when I go home and use this same laptop with a wifi connection to a linksys wgrt router connected to the internet thru a cable modem there is no problem. Or when I connect at any wifi hotspots in town. Its only here at work and this is a 100gps ethernet network connected thru the firewall machine to a 1.5mbps dsl line.